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Rod Dresser's Safelight Test
A prime cause of "depressed" highlights in a black and white print is safelight fogging. The cause is one or more of the following:
1. Too strong a bulb in the safelight.
2. Safelight too close to where the paper is being handled
3. Filter of safelight is defective.

We are addressing the problem of safelight fogging and not fogging due to out-of-date paper. It is mandatory, however, that you properly test for safelight fog in your darkroom. This applies even if you are using a darkroom that does not belong to you. In fact, many community darkrooms have safelights that are among the worst offenders.

My preference for an excellent safelight is a light fixture that contains a 15-watt bulb and a Kodak OC or Red Filter, which is sufficient for a small to medium sized space (80-100 square feet). You may wish to have a light above the developing tray, no closer than 48", to view emerging prints. However, I recommend a switch so that you can turn it on and off for short periods.

Under any circumstances, I implore you to test your safelight! If you make the standard test by leaving an opaque object on a piece of unexposed paper for four minutes and then developing it, you will probably get a pristine sheet of white paper. If you are satisfied with that result, you are deceiving yourself; you have not conducted a positive test and thus you may be subject to the anguish of safelight fogging.

A brief not too technical explanation is appropriate. Printing paper has various sensitivities and therefore responds to light depending upon the amount of light projected on it. This is another way of saying that there are thresholds of sensitivity to light. Let us, for example, expose a piece of paper to one unit of light and then a second equivalent unit of light. Next develop that piece of paper in your normal developer for your normal time. Let us assume that we get pure white with no hint of gray on our newly developed test print. Now, expose a new sheet of paper to two units of light and then one additional unit as before (second exposure). Again, develop normally and this time we observe a distinct overall gray. This coloration is due to the fact that we have reached the threshold of the paper with the first exposure (two units of light).

I have been purposely vague about the specific amounts of light, because of the aperture of the enlarger lens, developer, etc. What I wish to emphasize is that with very little more exposure we can get a significant color change. The corollary to the real world is that one never takes a fresh sheet of paper out of the box and puts it into the developer. The paper is already exposed to some quantity of light filtered through the negative. Thus, when the paper is put into the developer some of the silver salts have been exposed to light and reached or exceeded the threshold of sensitivity. Further exposure from any other source would cause the coloration of the grays to increase of depress. The dark shades of gray or black are going to be the least affected. They have already seen a good deal of light and a little more will be of less consequence. However, the lighter values, which saw little first exposure, will be seriously affected and depressed.

So how do we simulate this to realize an effective safelight test? Test all your papers regardless of sensitivity. Papers respond differently to the different areas of the light spectrum. Thus, a slower paper may fog faster than a sensitive one because of the particular filtered light source you are using.

Take a fresh sheet of paper and run a test strip using a translucent filter under your enlarger lens and negative in the carrier. Use the very smallest aperture stop on the enlarger lens. You can make a filter out of milky Plexiglas to insure that you get evenly diffused light projected on your paper. Use two-second steps in a test strip and get at least ten of the steps on the paper.

Develop the sheet normally, stop, fix and examine under your usual print viewing lamp. Look for the strip that has the same gray as Zone VII. This should be a full detail gray but quite light. We want it to be easily differentiated from the pure paper white. The tone color is not critical, but be sure it is a good solid light gray. Record the time of the strip that produces the Zone VII gray. Now expose one half of a new sheet to the recorded time, while covering the other half with an opaque material. Next, prior to developing the sheet, expose the sheet to the safelight for four minutes with an opaque object covering part of the sheet that had the enlarger exposure and part that was previously unexposed. Now, with the safelights out, develop the sheet, stop, and fix. Examine it under the viewing lamp in the darkroom. If you have a malfunctioning safelight, you will notice that the covered area of the sheet will be lighter than the rest of the exposed part of the sheet. The part of the sheet that was never exposed to the enlarger should show pure paper white.

A Guide to Lith Printing
Materials for Lith Printing
For Lith Printing (LP) you will use Cachet expo RF (glossy) or the Cachet/Maco LithPaper RC-F, the two-part, Macolith AB lith developer (liquid concentrate), a stop bath, Fixer, standard black & white darkroom equipment

What is Lith Printing?
Lith Printing (LP) is the process whereby a normally cold tone paper, after exposure, is developed in a combined two-part lith developer, producing a picture with a different image color, typically towards the warm brown; a compressed but clearly separated tonal gradation; and varied local contrast. Results from this process vary significantly depending on three things: Exposure time, developing time, and the paper used. The general rule for the LP is that you expose for highlights develop for shadow.

Exposure times for LP are generally longer than for standard black and white processing, up to two minutes and more. Processing times are also generally longer, Three minutes and up depending on developer temperature and exposure.

Another distinguishing characteristic of this process is that there are no standard times in lith printing; the print is pulled from the developer when it is "ready" according to a visual inspection of the print in the developing tray. The printer leaves the print in the developer until he or she sees a good black.

Cachet's expo RF and the Lith RC-F are well suited to Lith Printing. To begin with it is an excellent neutral/cold tone paper that has a specially formulated emulsion containing gold chloride and a load of silver, between 1.7 and 2.2 g/m² depending on the grade. Some b&w photographic papers currently marketed as HSC (high silver content) contain only 1.2 grams/m. expo RF contains no developers, optical brighteners or whiteners. These characteristics are the very things that make this paper such an excellent medium for lith print.ng and any kind of toning.

What is different about a Lith print and a standard black & white print?

* A shift of the image tone towards brown takes place.
* Compressed tonal scale, depending on the type of image, but tonal steps is clearly separated.
* Maximum density in the shadow areas will be increased.
* An apparent increase in acutance. A Lith print generally appears sharper than the same print produced on the same paper using standard developing techniques. This phenomenon could be the result of a slight jump in contrast.

Several approaches to Lith Printing have been published. The photographer Christos Mansousakis, who lives in Germany, has developed his own version of lith printing called the "MLD" technique. Tim Rudman has produced both an article, "Lith Printing," (PHOTO Techniques

July/August 1998) and very comprehensive book, "The Master Photographer's Lith Printing Course: A Definitive Guide to Creative Lith Printing." Master Printer Gene Nocon, one of the earliest experimenters with the process, devotes an entire chapter to lith printing in his book, "Photographic Printing."

How To Do It
The instructions you are about to read on lith printing will probably sound vague. And they are. Decidedly purposely so. The heart of lith printing is experimentation. Because there is so much creative latitude in this process, you will make up your own rules as you go along, dictated by the results you want.

Lith Developing - Dilutions for the Lith Printing method:
The standard dilution for Maco-Lith developer is as follows: First make a working solution by adding 1 part A plus ½ Part B plus 4 times the volume of A and B of water. Example: 100ml Part A + 50ml Part B to 600ml Water.

This mix is the working solution. Depending on what results you desire, the increase the dilution to 1:4, 1:8 or even 1:16. By doing so you will increase the development time, the shadows will be more "brownish" and the contrast grade will decrease

Working temperature:
The temperature of 68° F (20°C) is a good starting point. Achieve further variations by increasing the working temperature. At higher temperatures, both exposure times and developing times drop dramatically. For example, at Nocon's In House Lab in San Diego, he produces beautiful lith prints running at 95° F (35°) with exposure times at around one minute and developing times between two and three minutes.

*Warning Note:
From 25°C and higher, the developer will emit vapours that can irritate eyes and respiratory tracts. Be sure the darkroom is well ventilated when doing lith printing.

Exposure:
A good starting point for exposure is to make a print in regular developer and then add two stops. Example: if your exposure time is 20 sec, when processed in normal developer, your starting exposure would be 80 sec. when exposing for "Lith".

Developing:
One major difference between lith printing and standard printing is developing time. Most good printers pick a standard developing time and then build the process around that. In lith printing, one's judgement of the print in the developer determines the development time. Look for a good black and when you see it, "snatch" the print quickly. A certain amount of anticipation is necessary. As one experienced, lith printer put it, "If it looks right, you have already passed the mark."

Another thing peculiar to lith printing is that the whole development process is quite different from standard developing. With standard development, first traces of the image appear between 15 to 30 seconds and full development occurs after 2 to 5 minutes. Not so with lith printing. The image comes up very, very slowly; nothing happens for quite a long time; e.g. at 20° it can take up to five minutes.

However, do not get complacent. Once it starts, development moves very rapidly. This rapid developing is called "infectious development." Dissolved silver concentrates around exposed and latent silver halide crystals and goes unnoticed at first because it happens at a molecular level. Only after enough partially developed silver crystals are available and the degree of concentration of dissolved silver is high enough to be visible does the user recognise the changes taking place.

Agitation:
must be constant while developing or one may experience small round black spots. Develop with constant agitation and do not overuse the working solution. Spots that appear in the white edges of the print can be bleached out.

Stopping:
Especially important is a fresh and powerful stop bath to stop this fast infectious development immediately. The quality condition of the stop bath is important in maintaining control of image density.

Fixing:
Use a fixer at manufacturer's recommended dilution. Use a standard non-hardening fixer for two minutes or less. Be careful with extended immersion times; fixer can bleach the print.

Washing/Drying:
As usual with fiber base baryta papers.See also sections on the Cachet Fine Art Papers