PLATINUM PRINTING:
Platinum prints are prized for their warm, attractive appearance. They are super-archival and will remain unaffected by airborne contamination virtually forever (assuming the paper they are printed on does the same.) Platinum is inert to nearly all chemical reactions. Platinum prints have been recovered from sunken ships, smoke-damaged buildings and hazardous locations without any loss of image quality. Platinum printing is easy to do and forgiving of mistakes, as will be evidenced by following these instructions.
Stock Solutions
The sensitizer consists of the two small dropper bottles stored in the black plastic bag. The two larger (half-pint) bottles contain developer and fixer. All of these solutions are light-sensitive and should be stored out of the light.
Sensitizer: One bottle contains the platinum solution and the other the activator. They will be only slightly filled. Store in the black bag.
Developer: add water (preferably distilled) to the developer concentrate to make one pint (500 cc’s) of working solution, and store in a one-pint bottle marked “Developer” or dilute as needed, 1 part concentrate to 1 part water.
Fixer: add water (preferably distilled) to the fixer concentrate to make one quart (1L or 1000 cc’s) of working solution, and store in a one-quart bottle marked “Fixer” or dilute as needed, 1 part concentrate to 4 parts water.
Selecting Paper-- 10 Second Test:
The selection of the right paper for printing on is important. It should be smooth and bright. The amount of sizing in the paper is important: if the paper has too little sizing (the filler that boosts whiteness and limits absorption), much of the sensitizer will be lost in the fibers of the paper. Too much sizing, on the other hand, means that the sensitizer will not be absorbed.
Fortunately, most watercolor papers and many office papers meet an acceptable criteria of partial absorption. A quick test is to put a few drops of water onto the paper and spread it with a fingertip. Wait 10 seconds. If the drop is absorbed, that area of the paper will turn gray and the paper should not be used. If the paper remains white, it has limited absorbency and is okay for platinum printing.
Working Conditions
As a "daylight" process, platinum printing is relatively slow, so the chemicals can be handled under subdued light if daylight is avoided. Drying, which takes the longest time, should be done in near darkness. The only equipment for printing you will need is a printing frame or piece of glass to hold the full-size negative in contact with the platinum-sensitized paper plus some trays of the correct size, made of glass, plastic or stainless steel.
Obtaining A Negative
A full-size negative can come from many sources. Formerly, full size negative transparencies could only be made photographically, but technology now offers a method that
doesn't need a darkroom-- by digitally making a full-size transparency with an inkjet
or laser printer, or photo-copier.
You can start with any kind of original-- a black & white print, color print, black&white negative,
color negative, black&white or color slide, digital photograph, or an illustration
taken from a book or magazine. You can also start with a drawing or a solid object like a leaf (popular
with beginners.)
If you have a scanner or a digital camera, you can scan
the image and reverse it to make a black & white negative image, then print this onto transparency material with an inkjet or laser printer. Alternatively, some photo-copiers will scan and reverse an image and print it on transparency material.
If you don't have access to a scanner-printer combination or a photo-copier that can reverse, you can order a full-size negative transparency made from your artwork at an office-service store like OfficeMax or Kinko's.
You may prefer to make a full-size negative the traditional way-- photographically. You can do this by enlarging onto black-and-white litho film. If the litho film is a high-contrast type like Kodalith, develop it in paper-developer like weak Dektol instead of the high-contrast Kodalith developer.
Finally, you can make your own "litho film" by coating Liquid Light or Ag-Plus emulsion onto glass or clear acrylic.
Sensitizing
For an 8x10 inch working area, you will need one cc (20 drops) of sensitizer. Into the plastic cup, squeeze 10 drops (1/2 cc) from one of the small bottles in the black bag and the same amount from the other bottle. Swirl to mix the two solutions.
Dip the sponge brush in water, preferably distilled, and shake it hard to remove excess water. Pour the contents of the cup onto the center of the paper to be sensitized, which has been laid on a flat, smooth surface. Tilting the applicator brush forward, use the forward edge to spread the yellow liquid evenly over the paper in long, swirling strokes. (You might want to test this method with water before using the actual sensitizer.)
Drying after Coating
The paper should be dried in a current of air from a fan or hair-dryer. Drying time depends on temperature and humidity, but the paper should not be exposed until it feels definitely dry to the touch. Platinum paper stores badly, and should be used as soon as it is dry.
Exposing
A printing frame can be used, or if one is not available, a piece of glass. Glass should be ordinary single weight window glass in order to pass UV light, held down with weights at the corners. Exposure time should be long enough that you can see the color change from a medium yellow to a muddy yellow, but not long enough for it to become gray. Under full sunlight, this usually takes from
2 to 3 minutes.
Setting Up for Processing
You will need three trays for processing, made out of plastic, glass or stainless steel. Fill the first tray with the working solution of developer. Fill the last tray with the working solution of fixer.These solutions can be used repeatedly.
In the middle tray, pour a small amount-a half-pint or less- of fixer to serve as a stop-bath. The contents of this tray will become contaminated quickly, so the solution should be changed after every working session, or earlier if the it becomes yellow.
Developing & Fixing
Develop for 2 to 3 minutes at 60-75 degrees F with agitation. Drain the print and put it in the stop-bath with agitation for one minute. Drain the print and put it in the fixer for one minute with agitation.
Wash the print at least 5 minutes in cool running water. Blot and dry flat. After drying, the print can be flattened on a dry-mount press or with an electric iron on a low setting.