ROCKLAND COLLOID CORP.
Piermont, NY 10968

FREQUENTLY ASKED QUESTIONS

Here is an updated selection of questions we have received.
If you have questions or comments about any Rockland products, please let us know.

Enlargement Processes:

Setting up a darkroom
Emulsion printing
Do I need an enlarger?

Choice of safelight
Microwave oven for melting
Increasing contrast and speed

Spraying on emulsion
Use of Kodak Dektol & Fixer
Painting over emulsion
Processing oversize prints
Degree of transparency
ISO rating of emulsions
Archival qualities

Emulsion on handmade paper
Emulsion on ceramics and glass
Emulsion on an egg
Emulsion for templates
Contact-printing with emulsion

Overall graying
Adhesion problems
Out-of-date emulsion
Turns black upon fixing
Specks on aluminum

Room-Light Process:

About "room light" processes
Process color vs. pigment color
Sensitivity of processes
Making a full-size transparency
Establishing exposure
Nature of SelectaColor & Pyrofoto resists
SelectaColor on glass & ceramics
SelectaColor on metal
SelectaColor on illustration board

Pyrofoto firing

Tintypes:

Setting up a tintype studio
Equipment needed
Exposure questions
Tips for coating and developing
About tintype developer
Bulk tintype kits
ASA rating of tintypes
History of dry plate tintypes

Color Toners:

Streaks from Polytoner
Different toning processes
Inconsistent results
Purple stains from Halo-Chrome
Silver disappears in fixer
Sepia tones instead of silver
Use of Halo-Chrome with emulsions
Halo-Chrome with color paper

 

We have been using Liquid Light emulsion for years, but with Liquid Light VC (variable contrast) we are getting some overall graying. Is this the fault of the emulsion? Fog can come from too much safelight exposure or from fogged emulsion. The usual cause is the incorrect safelight. Use an amber or red safelight with Liquid Light or Ag-Plus. With LLVC, use a red safelight only. Test for fog by coating a few drops of emulsion on a file card, spreading with a fingertip, and waiting for it to set up. Develop one minute in Kodak Dektol diluted 1 to 2. It should stay white. If it turns gray, check the safelight. Back to top Can I use polycontrast filters with Liquid Light and Ag-Plus? With Liquid Light and Ag-Plus, do not use filters. They will only slow the emulsion down. You can vary the contrast by using an active print developer like Dektol for relatively high contrast (same as a #3 filter) or a soft-acting developer like Selectol Soft for lower contrast (same as a #1 filter.) Liquid Light VC, however, is a variable contrast emulsion that can be used with polycontrast filters. Back to top The print on Liquid Light looks normal until I put in the fixer, then it turns completely black. You're probably printing on a dark-colored background. The emulsion turns transparent upon fixing, so you lose contrast with the background. While the unexposed areas become transparent, the exposed areas are black. So if you process a print on a dark, say a black, background, the print will become black-on-black or invisible. You'll see this happening if you print on clear glass, too, as the image will seem to darken on fixing. If using standard developer like Dektol, you should print on light-colored backgrounds to give contrast to the print. Of course, you can print on a black background if you chose, if using the Tintype Developer instead of regular developer. With Tintype Developer, unlike conventional developer, the exposed areas of the turn whitish instead of black, so after fixing they stand out from the black background. Back to top Problems with adhesion You're using water as a shortstop. Do not use water for more than a second or two, or it will soften the emulsion as you describe. The better procedure is to divide a hardening fixer like Kodak Fixer into two baths and use the first bath as a shortstop. This will prevent any softening (see question on using Kodak Fixer). On varnished wood, the emulsion softens after development. The procedure for getting good adhesion on a varnished or painted surface consists of a few critical steps: Use only oil-based polyurethane finish (transparent) or alkyd paint (opaque), not any other type of pre-coat. Use a glossy finish, not satin or matte. Allow the pre-coat to dry thoroughly before coating with emulsion. Let the emulsion air-dry in a warm, dry open place with circulating air (the emulsion can be thoroughly dried, or only partially dried.) Develop in paper developer, not film developer. Rinse only a second or two (see the paragraph above.) Use Kodak Fixer, not rapid fixer, and fix until the surface becomes leathery before washing. Back to top Liquid Light works fine on a test strip I made using a file card, but not on the handmade paper I am using, which requires a much longer exposure. The paper is absorbing all the emulsion, so light from the enlarger can't reach it. Use two coats. Let the first coat soak into the paper for a few minutes, then give another coat at right angles to the first. Let it set up a few minutes then expose while the emulsion is damp or dry. Back to top What causes little black specks on aluminum that has been primed with polyurethane? The polyurethane is leaving pinholes, and these are causing a reaction with the silver in the emulsion. The remedy is to give two coats of glossy (not satin or matte) polyurethane. Let the first coat get barely dry, give a second coat and really dry this coat well in warm moving air at least overnight before applying Liquid Light or Ag-Plus. Back to top What's the best safelight to use with liquid emulsions? With Liquid Light or Ag-Plus, use a light amber (OC) or medium amber (13) safelight, preferably the former as it gives much more light. You can also use a light red (1A) or medium red (1) safelight with Liquid Light. With Liquid Light VC, use a light red (1A) or medium red (1) safelight, preferably the former because it gives much more light. Do not use an amber safelight with Liquid Light VC. What's the difference between preparing glass and ceramics with glossy polyurethane and the gelatin subbing? Both methods seem to work okay. With the subbing method, the emulsion fuses directly to the ceramic or glass for an effect you won't get with polyurethane, so it is the first choice. But subbing won't work with plastics or with glass-like materials like Plexiglas or Lucite, only with true mineral glass or glazed ceramics. If in doubt, use glossy polyurethane*. It will provide adhesion on virtually any material-- glass, ceramics, metals, rocks, etc.-- and will also seal the pores of many porous materials like wood, bisqueware, etc. where developer and fixer can seep in and eventually cause fading. * Note the word "glossy". Satin or matte-finish polyurethane contain waxes and won't give the same degree of adhesion. For glazing (see next paragraph), the subbing technique is necessary. Back to top I'm a ceramicist, not a photographer. I'd like to take the extra step of glazing an image on my photo-ceramics. What process should I use? With a photographic emulsion like Liquid Light or Ag-Plus, you can print on a surface with compound curves such as a bowl or sculpture. You'll need an enlarger or slide projector, a darkroom with safelight, and some black & white developer and fixer. The result is permanent and shows a black full-range image against a transparent background. It is designed for display, not hard use or immersion. (Emulsion, processing chemicals and Pyrophoto can be purchased separately or in a combined package.) SelectaColor is a way to print in color. No darkroom is needed. Simply coat any semi-absorbent or non-absorbent surface and expose with a bright light source like a quartz-halogen bulb or sunlight (see instructions for SelectaColor.) The process is recommended for flat surfaces and simple shapes. Pyrofoto is a color process specifically designed for kiln-firing on ceramics and glass, where it forms an impervious image suitable for outdoor use and food-service. See Pyrofoto instructions. Back to top I would like to use a large sheet of steel, primed, about 6' high and 3' wide...How can I fix...stop bath etc. and do a final wash on such a large piece? Processing pieces of any size is easiest with a tray, but big trays are hard to find. Sometimes people build them out of plywood that is well varnished to make them water-tight. An alternative is to use a stretched canvas as a tray, using a sealant where the nails or staples enter the stretcher. Without a tray, apply developer (Kodak Dektol diluted 1 to 2) with a soft roller or spraying with a refillable bug sprayer. Do not use a shortstop. Apply Kodak Fixer liberally. The function of the fixer is to wash away certain chemicals in the emulsion, so it should be applied repeatedly until the image has cleared. You could make a trough to catch the fixer and re-circulate it. Fix until the surface turns leathery, about 5 to 10 minutes, but longer won't hurt. Wash well with a spray, roller or other source of water about 10 minutes. Back to top I have some emulsion with a date that is six months past due. Is it still usable? It probably is. There are two tests you can do. First, tilt the bottle gently at room temperature (about 70 deg. F). It should be a solid gel, not a liquid. If it passes this test, melt some emulsion and under safelight spread a few drops on a file card. Let it set up, then develop without exposing it. If the emulsion stays white and does not turn gray or black, it is okay. Back to top What is the approximate ISO rating of Rockland emulsions? Unlike conventional black and white films, liquid emulsions are not panchromatic (sensitive to all colors) but only to blue light. If you are using the emulsion in a camera, put a piece of blue acetate (any shade is okay) in front your exposure meter. Once the exposure is calibrated, you can expose consistently from shot to shot, as you are measuring only blue light. To calibrate, start test exposures with an arbitrary ISO or ASA setting such as the low double digits. Note that sensitivity may vary from batch to batch, represented by the date stamped on the box. Back to top How can I increase the contrast of the emulsion? You can get maximum contrast and density by sensitizing the emulsion with a small amount of developer. One method is to add exactly one part of working developer (not concentrate) to 10 parts of emulsion before use. Sensitize only as much emulsion as you plan to use within one day, as the mixture will not keep. Another method is to sensitize the emulsion after coating and before before exposing. Immerse the object that has been coated with emulsion in working developer for 30 seconds, then drain and put it on the easel and expose it (this can be messy, so use some paper towels.) Develop and fix normally. With both these techniques, the speed as well as contrast will be increased, so do a test strip before exposing. Back to top You suggest the use of Kodak Dektol developer, and Kodak Fixer as a fixer. Is there a reason for choosing these specific products? Kodak Dektol is our first choice because because it's resistant to fog (overall graying) of the emulsion. Some developers, particularly those that are sold as highly concentrated liquids, promote fogging. We use 2 parts of water per one part of Dektol stock solution. Whichever developer you choose, be sure it is a paper developer, not film developer. We recommend Kodak Fixer because (1) it hardens the emulsion more effectively than any fixer we have tested and (2) because it is non-fading, unlike some "rapid" fixers that will dissolve away part of the image while they work. We use Kodak Fixer as a straight stock solution, until the emulsion clears and the surface becomes leathery to the touch (about 5 minutes.) Both Kodak Dektol and Kodak Fixer come as powder in a yellow packet and must be dissolved to make stock solutions-- a minor inconvenience in view of their advantages. Back to top Can Liquid Light or Ag-Plus be applied by spray? Yes, but spraying is not the preferred way of coating emulsion. Because photographic emulsion is temperature-sensitive and tends to gel at cool temperatures, if sprayed it forms a rough pelletized coating instead of a smooth one. The exception is a "curtain" spray, that applies emulsion in a liquid state instead of an aerosol, followed immediately by chilling to set the layer; however, this method is usually done only in professional labs. The most practical way to coat in the average darkroom is to to flow on or dip the emulsion, applying multiple coats if desired, with drying or partial drying between coats (see instructions). Coating can also be done by brush, with multiple coats applied at right angles to minimize streaking. If spray coating, make sure the spraygun has no parts of brass, steel (except stainless), copper or other metals. Back to top Are there problems with painting over a Liquid Light image with oil-based paints? Not if the emulsion is well hardened, washed and dried. If in doubt, a coat of water-based polyurethane to promote adhesion is a good idea (coat thinly to avoid streaks.) Or you can use Marshall's photo-oil paints. Back to top In general, if you applied Liquid Light to a glass plate, would an unexposed area appear clear, translucent, or have some color or other cast to it? The unexposed areas will stay clear while the exposed areas will turn black, depending on the degree of exposure. If a toner like Polytoner is used, the unexposed areas will be clear and the exposed areas will become the selected color. With Printint, the unexposed areas are tinted the selected color while the exposed areas will stay black. Back to top I was wondering, has anybody ever printed on the surface of eggs, and should I try? First wipe the eggs with cigarette-lighter fluid to remove any wax, as eggs are often dipped in wax, followed by hot water and washing soda (or powdered laundry detergent) to chemically-clean them. They should then be "subbed" as described in the instructions before coating with emulsion. Back to top Can I use a microwave oven to liquify the emulsion instead of putting the bottle in hot water? Yes you can, but be very careful not to overheat the emulsion. Only a few seconds are necessary to start melting the emulsion. If you want to liquify the whole bottle, use "on" cycles of a few seconds and turn the bottle between cycles. Back to top What are the archival qualities of Liquid Light? Liquid Light and Ag-Plus prints consist of colloidal silver grains in a gelatin binder. This is similar to the chemistry of conventional black and white prints, which are archival if properly processed and adequately washed to remove all processing chemicals. The chance of fading is even less with liquid emulsion prints because the amount of silver is usually greater than in conventional black and white prints. In terms of practical experience, liquid emulsion prints also greatly outlast digital prints. We have prints that are decades old and unprotected from the air, that show no sign of fading or degradation. Back to top I want to make a print on ceramics with Liquid Light but don't have an enlarger. Can I make a contact print, assuming I have a full-size inkjet negative? Sure you can, providing the surface is flat or has a simple curve, allowing the negative to sit in close contact with the emulsion while the exposure is being made. One word of caution, though. The biggest trap in contact printing is over-exposure, as Liquid Light and Ag-Plus are sensitive to full light. A good starting point is easy to remember: 4-4-4. That is 4 seconds exposure with a 40-watt bulb at a distance of 4 feet. Back to top Which emulsions are good for making templates? Templates or full-sized patterns are often used in metalworking, particularly in the aircraft industry. Liquid Light or Ag-Plus can either be used for this purpose, applied by brush or spray to a sheet of metal that has been prepared for adhesion and to isolate the emulsion from the substrate. Preparation is most often done with glossy polyurethane varnish. The emulsion is applied and exposed with an enlarger or slide projector. After processing, a line drawing of the pattern is imprinted full-size on the substrate, where it can serve as a guide for cutting or other processing. Another product that is used for templates is Rockland SelectaColor. It is a photo-resist that washes off after exposure to reveal a bright positive image. Any color can be used, but blue is generally the fastest. Unlike Liquid Light and Ag-Plus, SelectaColor is a contact-speed sensitizer, so it must be exposed by contact printing with bright lights using a full-size negative. Back to top Why are SelectaColor, Pyrofoto and classic processes often called "room light" processes? Because unlike emulsions, they do not require a darkroom and can be handled under subdued room light. They include SelectaColor and other alternative processes. They are contact-printed under a full-size negative, using bright lamps or sunlight. Back to top Some processes like SelectaColor, Pyrofoto, FA-1 sensitizer and blueprint require a full-size negative for contact-printing. I'd like to make such a negative from a color print. How do I go about it? Formerly, full size negative transparencies could only be made photographically, but now they can be made digitally with any inkjet or laser printer, or photo-copier. See "Transparencies" on the Products page. Back to top I'd like to transfer a color print to metal. Can I do it with SelectaColor? Color prints consist of dyes. Dyes are transparent, to allow colors to add together to make "process" color. Example, blue on yellow gives green. Because they are transparent, dyes show up only against a white background (color print) or when light is shone through them (color transparency.) Against any other background, they disappear. Try holding a color transparency against a metal background and see what you get-- nothing. Rockland processes like SelectaColor, on the other hand, consist of solid pigments. They are not transparent, so they will show up brilliantly against any contrasting background. They are designed to be applied to all sorts of materials of different colors and textures, so in the previous example with a metal background, the image will be bright and contrasty. Pigments have other advantages over process colors such as resistance to fading, and can be exposed in sequence for combinations of colors. Back to top What is the sensitivity of the room-light processes? Each process has different sensitivities but in general the closer you get to the spectrum of sunlight, the shorter the exposure will be. Next to sunlight itself, the fastest exposures are with a high-wattage halogen bulb, mercury vapor lamp, sunlamp, arc light, blue photofloods, daylight florescents or UV fluorescents. Back to top I have been using Halo-Chrome for years, but recently there have been inconsistent results that I am sure are not caused by my procedure. Usually this is caused by old or stale enlargement paper. First , test the HC to be sure it's working correctly: Under room light, develop a small piece of freshly dated enlargement paper for one minute. It will turn black, of course. Rinse and fix in Kodak Fixer (not a liquid fixer) for 2 minutes, wash 5 minutes and bleach in the HC bleach until the black completely disappears. Then rinse one minute and develop in HC diluted 1 to 7 as per instructions. The paper should turn silver. If so, the paper you are having trouble with should be discarded for a fresher batch. Back to top There is a purple stain when I do Halo-Chrome prints. It's normal to have a stain after processing with Halo-Chrome. After the print has been made, remove the stain with a hypo-base fixer like Kodak Fixer (see below). Back to top Notes on combining silver toning with process color An unusual and beautiful process with Halo-Chrome combines metallic silver with process color. To start, develop a Type C color print in the normal fashion. After development has taken place but before bleach-fixing, the print still retains a large amount of residual silver. If it is placed in Halo-Chrome at this time, the entire surface of the print will become metallic due to this retained silver. Room lights can now be turned on, since the color image is protected against exposure by a layer of metallic silver. At the same time, the contours of the subject underneath can be detected beneath the solid silver. Using a brush dipped into bleach/fix, it is then possible to selectively remove the metallic silver, revealing the color image underneath. Areas that have received the bleach-fix will appear in process color; the unbleached areas will remain as solid metallic silver. That's all there is to the process, resulting in a print that has areas of process color and others pure metallic silver, a truly unique combination. Back to top The silvering went fine with my Halo-Chrome toner, but when I put the print in the fixing bath, the silver disappeared. What went wrong? You used the wrong fixer, probably a liquid fixer, also known as "rapid" fixer. Rapid fixers, based on ammonium thiosulfate, often can cause bleaching of a print. Only hypo-based fixers (those using sodium thiosulfate) will fix and harden a print without bleaching. This is why we strongly recommend a hypo-based hardening fixer over rapid fixers for use with all Rockland products. The most available of these is Kodak Fixer, sold as a powder; there are a few others. Back to top I bleached and toned the Halo-Chrome print according to instructions, but not much of the picture is silver, it is more sepia. The silvering will be complete in the totally exposed areas. That is why we recommend a high-contrast negative. In intermediate areas, the silver will look brownish because the layer of silver is too thin to see. For best silvering, use a negative with strong blacks and clear highlights for contrast. Back to top Can I use Halo-Chrome with Liquid Light emulsion? You can, but the results will be better with Ag-Plus emulsion. The best results with Halo-Chrome are obtained with conventional black&white papers. Back to top I'm confused about the different ways of coloring black and white prints. What is the difference between toning, tinting, etc.? Toning is a chemical reaction between the silver image and a dye-former, creating a color in proportion to the density of the silver image. Rockland Polytoner falls into this category; so do conventional sepia toners; so, too, does Halo-Chrome. Tinting, on the other hand, uses dyes that soak into the emulsion uniformly and are brightest where the silver is least, usually the background highlights. Rockland Tintint colors fall into this category. Theoretically, it's possible to make a print that is both toned and tinted. Back to top There are streaks on the print after using Polytoner. The color couplers in Polytoner are water-insoluble until mixed with alcohol, so it's important that you mix the chemicals in the order given-- developer, coupler, activator and water-- as described on page one of the instructions. Back to top I've never done photographic printing. What is the procedure? Since photographic emulsions are highly sensitive to light, they require a darkroom for safe handling. A darkroom is simply a small working area that shuts out room light and relies on a safelight, usually an amber or red bulb.You will need some print developer like Kodak Dektol and a hardening fixer like Kodak Fixer, plus three trays for processing. Running water is a convenience, if available. An enlarger or slide projector is the only major piece of equipment you may need (see below). Its function is to enlarge a small black-and-white negative into a large positive image. The price of new enlargers, available at larger photo stores or our website, ranges from $150 upward. Used enlargers can be bought on e-Bay or from ads in photo magazines. If you don't have an enlarger, a satisfactory substitute is a slide projector. Sources: Much valuable information is contained online in Wikipedia under "Darkroom" or from a Google search. Another useful site is "The Black&White Darkroom" by Barry McCartney. Do I need an enlarger? An enlarger or slide projector allows you to to use emulsions to their fullest extent: You can print on three-dimensional objects like photo-sculpture, photo-ceramics, mixed media works, murals-- in fact, on any size or shape or material. However, many useful processes like SelectaColor as well as the so-called alternative photography are "room light" processes that don't need an enlarger, or even a darkroom. They are handled under dim incandescent light and exposed by sunlight, sunlamp or other source of bright light. Room light processes do require a full-size transparency (for information on making transparencies, click here.) The only limitation is that you must print on a fairly flat surface since the transparency must be held in close contact with the sensitized surface. Back Areas of the tintype that should be pure black are kind of hazy, lowering the overall contrast of the print. The tintype developer may be too fresh, causing a haze. The remedy for this is to leave the solution in an open tray overnight to "season" it. Other sources of loss of contrast are light leaks of any kind or overexposure. Too thick a coating of emulsion can also cause a hazy picture that is low in contrast. Areas that should be black (that are unexposed) have a slight haze. This is sign of fogging, and maya be caused if the emulsion is fogged (a test for this can be done with Dektol), it is too fresh (it should be at least 24 hours aged after mixing), if the development time is too short (it should be at least 3 minutes), if fixing was not complete, or if the emulsion has been coated too thickly. Areas of the tintype that should have an image are black, so there is almost no picture. This can come from the tintype developer being oxidized, indicated by its turning brown. A pinch of Dektol in the developer may help. Another reason is underexposure (see below.) This seldom happens when tintypes are made outdoors in the camera, because sunlight is rich in the blue spectrum, but happens easily indoors. Back to top How do I determine correct exposure? For consistent exposures outdoors, hold a blue filter over the light-entrance of the exposure meter (any scrap of blue acetate will do.) This will filter out all light except blue, that is the only part of the spectrum that Ag-Plus is sensitive to. Use this setting to get consistent exposures through a variety of outdoor lighting conditions. If you're making tintypes from color slides in an enlarger, do a test strip to determine correct exposure. Coat a few drops of emulsion on an index card, expose with the color slide, and develop like a normal print in Dektol or other paper developer. The image will come out negative, of course, but disregard this and aim only for correct exposure, then use the same exposure with the Tintype Developer. Back to top How should I coat and develop my tintypes for best results? Coat thinly and develop fully. Pour on some emulsion, spread it quickly and pour off the surplus for re-use. Set the plate on a flat surface and cool it as quickly as possible to firm up the emulsion and prevent it from running down the "peaks" into the "valleys". (A minute or two in a refrigerator or under an air-conditioner is excellent, if available.) When the emulsion has set up, stand the plate up and dry it thoroughly under warm moving air from an electric fan. The dried plate should appear medium to fairly dark gray under safelight. Determine a satisfactory exposure and expose the plate. Develop with constant agitation, and always develop at least two minutes. First the plate will turn black, then a picture will slowly emerge. This may take even longer, but that's okay as long as the developer is agitated. Do not worry about over-development as long as agitation is maintained. If development time is too brief, areas of the print may have a bluish cast. If a plate is not satisfactory and you want to reclaim it, the best method is to run hot water from the tap over it and scrub with a wet, not too stiff, bristle brush until all residual emulsion is eliminated. The plate can be dried and re-used. Are bulk tintypes handled the same as the Tintype Parlor kit, and can I make my own plates for coating? Yes, with minor differences. The bulk kit contains everything but fixer, which you supply- preferably Kodak Fixer, available at all photo shops or from our website. Or you may choose to take the extra step of making your own plates for coating with emulsion. (You can make plates for coating out of sheet metal coated with black household enamel, available at all paint stores.) In that case, order just Ag-Plus emulsion for coating plus the Tintype Developer for reversal development. Back to top What's the difference between wet-plate (collodion) and dry-plate tintypes (like Rockland's)? From Robert Leggat's "A History of Photography" (1999): "The development of the Collodion process marked a watershed in the development of photography. However, this wet-plate process had limitations, one being that it was necessary to keep the collodion moist. For a number of years several attempts were made to discover ways of keeping the collodion moist for long periods. The materials tried included unusual ones like licorice, beer and raspberry syrup! Some success was achieved by using a mixture of bromide in collodion. The ideal binder would be one which enabled the plates to be used only when dry. It was not until 1871 that the next breakthrough was achieved by Dr Richard Leach Maddox, when he began using gelatin. In fact, as far back as 1850 Robert Bingham had suggested the use of gelatin, but this idea had not been taken up at the time, presumably because of the announcement of the collodion process the following year. "Gelatin is a protein obtained from animals, which is transparent and odourless, and used in a number of food processes. The first account of its use in photography is in the British Journal of Photography for 8 September 1871, when Maddox suggested that the sensitising chemicals could be coated on to a glass plate in a gelatin rather than a collodion emulsion. Maddox's process, though revolutionary, was far slower than collodion. Several manufacturers experimented with it, the most successful being Charles Bennett, who in 1878 announced a new gelatin dry plate process. This was a major breakthrough, particularly since Bennett's process also considerably enhanced the sensitivity of the emulsion, reducing the exposure time to one tenth of that required for the collodion one. "The dry process relieved photographers of the need to carry about their own darkroom and chemicals; exposure could now be made on location, development being left until much later; it also let to a greater degree of standardisation, and a more scientific approach to photography; the science of sensitometry was introduced at around this period, and exposure calculators now began to appear. By the end of that decade the dry plate had superseded the wet plate entirely." Note: Rockland tintypes use the dry plate process, which we prefer because unlike the wet plate process, dry plates tintypes are non-flammable, fume-free and safe to use in the darkroom. Back to top What equipment do I need to make tintypes? The requirements are fairly simple. You will need a dark area lighted by a safelight for coating the emulsion on metal plates. The safelight can be a conventional one, or you can make a satisfactory substitute with a red bulb of 15 watts or less at a safe distance. You will need three trays of the correct size made of plastic, glass or rubber for processing. Running water is a convenience. You can make tintype plates either in a camera or by projecting a color slide onto the plate. The traditional way is with a camera that holds 4x5 inch or larger plates. Cameras like this are fairly easy to obtain and they often come with film holders that can be adapted to hold tintype plates. Tip: For a good fit with most 4x5 film holders, cut 1/8" off the top and 1/4" off one side to reduce the plate to 4 7/8"x 3 3/4" using sturdy shears or an office paper cutter. An old bellows-type camera can be adapted for tintypes, with each plate cut to fit as needed and loaded in the darkroom. (Caution: There's a chance that metal tintype plates will scratch the camera, so don't use a valuable camera without being very careful.) Also a pinhole camera is often used to make tintypes. Outdoors, for consistently correct exposures, an exposure meter is convenient. Since the emulsion is only sensitive to blue light, cover the opening of the meter with a blue acetate to eliminate other wavelengths; this will give a more accurate reading. Indoors, exposures will be much longer, as long as a minute. For lighting, you need a rich source of bright blue, such as a high-wattage halogen bulb, Photoflood lights, or daylight fluorescents. Finally, you will need some old tintype-period costumes, that are available at theatrical costumers or, if you're lucky, from your attic. Tintypes will look most attractive in special frames. Some links to companies that make attractive paper frames are: www.ginabear.com, www.pennphoto.com and www.canadamounts.com. Back to top Results are inconsistent. I'm not sure I'm exposing correctly. To use SelectaColor initially, test it on the base material (substrate) you intend to use. Wipe some sensitizer with a cloth thinly onto the substrate, let it air-dry and cover half the coated area. Expose for a period of, say, 2 minutes using the light source you have chosen. Wipe off with a damp sponge. The exposed portion should be colored, and the unexposed portion clear. Adjust the exposure time as needed. Once results are obtained, you can factor in the additional exposure required by the transparency. This procedure should be repeated for all colors, as some (blue) are more light-sensitive than others (red). Remember to keep the coating as thin as possible, so light can penetrate down to the base. Back to top Please tell me ASA rating or the film speed that tintypes are sensitive to. Tintypes are made with liquid emulsion that is sensitive only to blue light, unlike most films which are panchromatic or sensitive to all colors. So liquid emulsion speed cannot be measured the same as film speed, being very sensitive to daylight that is rich in blue and insensitive to incandescent light that is poor in blue. That's why we recommend a blue acetate over your exposure meter in order to measure only blue light and thus get consistent results. Start at a low ASA, around 20 for exposure tests. Back to top SelectaColor and Pyrofoto are called "photo-resists". What exactly is a photo-resist and how does it differ from conventional print-making techniques like photographic emulsion? Photo-resist is basically a process where an image is exposed through a transparency, and after exposing, is "washed out," leaving behind just the exposed areas. It is used extensively in printing. Some photo-resists are washed out after exposure with special solvents and others, like SelectaColor, with plain water. The parts of the image that have been exposed to light are hardened, while the unexposed areas are water-soluble and disappear down the drain. By their nature, photo-resists are capable of a wide range of effects depending on what they are made of. In pigmented SelectaColor, the resist consists of finely dispersed pigments that are solid particles of color and after wash-out make an extremely bright and durable image. By substituting ceramic stains for pigments in clear SelectaColor, images can be fired on glass and ceramics. By contrast, photographic emulsions form a continuous film that is visible in the exposed areas and transparent in the unexposed parts-- just as effective in printmaking but without the brilliant and lasting colors possible from pigments. Back to top How do I get the best adhesion to glass and glazed ceramics? Unlike emulsions like Liquid Light that need a primer before applying to glass, SelectaColor will normally stick to glass and glazed ceramics provided the surface is chemically clean. Do do this, use hot water and washing soda, available at large grocery stores(not baking soda). Scrub the glass or ceramic until the rinse water does not bead up when drained off. Air-dry then coat with SelectaColor. Back to top I coated SelectaColor on copper for making a photo-etching. It hardened even in the non-exposed areas. What went wrong? There was a chemical reaction between the copper metal and the metallic compounds in SelectaColor. To prevent this, pre-coat the copper with an insulating layer consisting of a solvent film and coat the SelectaColor on top of it. Typical solvent film-formers are shellac (soluble in alcohol/acetone) and lacquer (soluble in lacquer thinner.) After exposure and wash-off of the sensitizer, the film can be removed with these solvents. Back to top I want to transfer a line drawing on paper onto illustration board. Normally, I'd trace it with carbon paper, which takes effort and time. Is there a quicker way? First make a transparency of the drawing. Coat the illustration board with SelectaColor sensitizer (any color is okay but blue is preferred). Expose, then wipe the board with a damp sponge. The unexposed areas will wipe away, leaving a copy of the drawing. Back to top Can I use Dektol or other paper developer instead of Rockland Tintype Developer to make tintype plates? Sorry, no. Bear in mind that tintypes are printed on black plates, so if you use ordinary paper developer you'll get a black image, or black-on-black. Tintype Developer, on the other hand, will yield a light-colored image that will show up against the black background. For tintypes or ambrotypes, use Rockland Tintype Developer. (The same emulsion-- Ag-Plus-- is also used for normal prints against a light-colored background. In this case, of course, use Dektol or other paper developer.) Back to top Back to Home Page