Search in book...
Toggle Font Controls
Create new playlist

Name your new playlist

Playlist description (optional)
Sign In

Email address

Password

Forgot Password?

or

Continue with Facebook

Continue with Google
Sign Up

Full Name

Email address

Confirm Email Address

Password

or

Continue with Facebook

Continue with Google

A wide variety of commercially prepared formulas are available for use in photographic processes. These prepared formulas are accurately compounded and easy to mix, and they provide reliable purity and uniformity that ensures consistent high-quality results.

Conversely, there are numerous reasons to prepare your own photographic formulas. It can be valuable for a photographer to know how to prepare a formula from scratch. Mixing your own formulas can provide a clear, concrete cause-and-effect demonstration of how various photographic processes work. This understanding can be applied to achieving more precise control of the medium. Mixing your own formulas also can be less expensive than buying packaged preparations and allows you to utilize formulas that are no longer commercially available. This process offers further visual adventures, and is enjoyable and gratifying.

This chapter provides the fundamental background in terms of equipment and methodology necessary to begin experimenting with nonprepared photographic formulas. Specific tried and true formulas and process details are included in the appropriate chapter sections dealing with specific processes. Although no previous expertise is required, one needs to read and follow all handling, mixing, and safety instructions included with the chemicals being used before preparing any formula. Also read and follow all the general safety guidelines outlined in Addendum 1. Protect yourself by wearing protective equipment such as safety glasses, a plastic apron, rubber gloves, and a mask to avoid allergic reactions, burns, and irritation to the skin or lungs.

Basic Equipment

Many photographers already have most of the items needed to prepare their own formulas. These include graduates, mixing containers, stirring rods or paddles, a funnel, an accurate thermometer, opaque storage bottles, protective gear, and a well-ventilated area that is not used for preparing food and is free from children and animals. The items that may be lacking are a scale and a mortar and pestle. All equipment must be made of nonporous and easy to wash materials.

Figure 5.1 *Boy and Girl Chemists,* from Robert Brent's *The Golden Books of Chemistry Experiments: How to Set up a Home Laboratory — Over 200 Simple Experiments.* Illustrated by Harry Lazarus. New York: Golden Press, 1960.

Courtesy Gary Nickard Collection.

Scales: Mechanical and Electronic

A small, accurate scale is essential for weighing chemicals. Scales are available in a variety of sizes, styles, and price ranges. Balance scales are recommended because they are reliable, affordable, long-lived, easy to use, and do not require batteries or electricity. When purchasing a balance scale, be sure the sliding scale is easy to read and that the scale has removable pans for convenience of use and cleaning. The Ohaus Scale Corporation makes a mechanical triple-beam balance scale that is superb for photographic purposes. The scale is sensitive to 0.1 gram and its standard capacity range is suitable for most individual needs and can be extended with attachment weights. If you plan on doing a good deal of your own mixing, this durable scale is a good investment and affordable vintage models can be found online.

Electronic digital scales have replaced many of the lower priced triple-beam balance scales. These scales, often battery powered, are available for those who want a simple LCD readout. Most digital scales will calculate Tare weights with a push of a button. Tare weight is the mass of the container that holds what is being weighed. The Tare weight button automatically subtracts the weight of the container so that only the actual substance (chemical) is weighed. They are commonly used at grocery store checkouts.

Scales and other mixing equipment mentioned in this chapter can be ordered over the Internet, through mail-order photo and scientific houses, from chemical supply houses, or directly from the manufacturer (see Table 5.1).

Mortar and Pestle

A mortar and pestle made out of glass or porcelain is useful for crushing, grinding, and mixing dry chemicals that are not in powder or grain form. Do not use marble or wooden sets, as they will absorb chemicals and could contaminate other formulas.

Spoons

A set of plastic or stainless steel spoons for transferring chemicals from the bottle to the scale can prevent messy spills that are wasteful and can cause contamination.

Mixing Equipment

Accurate, easy-to-read graduates in small and large sizes, clearly marked in both milliliters (ml) and ounces (oz), are essential. Plastic containers of various sizes make good mixing pails and stirring paddles are helpful for mixing.

Table 5.1 Laboratory Equipment Suppliers

Edmund Scientific	www.scientificsonline.com
Lab Safety Supply Inc.	www.labsafety.com
Ward's Natural Science	www.wardsci.com
Ohaus Scale Corporation	www.ohaus.com

Storage Containers

Different sized brown or opaque bottles made of glass or plastic make excellent storage containers for mixed solutions. Opaque containers prevent deterioration caused by light. Plastic is more durable than glass and can be squeezed to eliminate most of the air to lessen the effects of oxidation. Bear in mind all plastic containers absorb chemistry over time. Keep similar chemistry in the same containers and replace plastic containers periodically. Medicine-dropper bottles, available at drugstores, are excellent for keeping small amounts of expensive solutions.

Certain chemicals are hygroscopic (absorbing water from the air) and can form a hard crust upon exposure to air. Others are efflorescent, losing their normal water content when exposed to air. Either of these conditions can make accurate weighing impossible. Still other chemicals can evaporate or fume. Avoid these problems by tightening the lids on all bottles. Clearly label every bottle with its contents and the date it was mixed.

Chemicals

Obtaining Chemicals

One can obtain many of the chemicals used in contemporary processes from large photography stores. When working with some of the more unusual or older processes, obtaining the required chemicals can be more problematic. Check with a chemical supply company (see Table 5.2). Some companies may not sell chemicals in small quantities for individual use. If possible, purchase through a business or educational facility. A few companies specialize in stocking photographic chemicals. Check the ads in photography publications or online for information on suppliers.

The prices of chemicals can vary dramatically, so shop around. In addition, manufacturers often give different trade names to the same chemical. For example, the developing agent methylaminophenol sulfate is known as Kodak Elon, Agfa Metol, Pictol, and Rhodol. Spelling also can vary. For instance, the British spelling of sodium sulfite is sodium sulphite and the British spelling of sodium sulfate is sodium sulphate. Chemicals come in three different classifications or grades that reflect their purity (see Box 5.1). Be sure the price obtained is for the exact grade of the chemical required.

Figure 5.2 To get the visual results he wanted from printing-out paper, Hunter needed a negative with much greater than normal contrast. He achieved this by rating 8 × 10 inch TRI-X film at 100 and developing it in modified Pyro ABC developer. The printed-out image was treated with Gold Chloride Toner, producing a lavender tone.

Box 5.1 Chemical Classifications/Grades

1. Analytical Reagent (AR) is the highest standard for purity and uniformity. This grade is the most expensive and is not needed for most photographic purposes. It is usually labeled ACS (American Chemical Specification). In the UK, it is labeled ANALAR.

2. Pharmaceutical or Practical is about 97 per cent pure and can be used for almost all-photographic work. It is labeled USP (US Pharmacopoeia) or NF (National Formulary). In the UK, it is labeled either BP (British Pharmacopoeia) or BPC (British Pharmaceutical Codex).

3. Technical or Commercial is approximately 95 per cent pure and is subject to variations that could alter the visual outcome. It is not recommended for critical work.

Table 5.2 Sources of Photographic Chemicals

Artcraft Chemicals	www.artcraftchemicals.com
Bostick & Sullivan	www.bostick-sullivan.com
Photographers’ Formulary	www.photoformulary.com
Rockland Colloid	www.rockaloid.com
VWR Scientific	www.vwrsp.com

Chemical Storage

Keep all chemicals away from all living creatures. If necessary, lock them up. Label and date all bottles of mixed solutions. Be sure storage bottles are securely capped. Protect all chemicals from air, heat, light, moisture, and contamination from other chemicals.

Chemical Disposal and Safety

When working with any chemical, you assume the responsibility for its safe use and disposal. Follow any special instructions included with each chemical or process being used as well as the safety recommendations in Addendum 1. Laws concerning disposal of chemicals vary widely. Check with your local health department to get guidelines Hazardous liquids can be poured onto kitty litter and placed in a plastic bag. Dry chemicals or contaminated materials can be disposed of by sealing them in a plastic bag. Both should be put in a closed outside dumpster. Do not mix liquid and solid wastes together, as dangerous reactions might occur.

Figure 5.3 Eshbaugh piggybacked two rolls of 120 film and exposed them simultaneously using his handmade pinhole camera. After developing the film in Sprint chemistry, he montaged images from the two rolls of film and printed that image on Ilford Warmtone fiber base paper. The artist then lightly selenium toned the photograph (1:10 dilution), which was followed by selectively applying a copper toner and finally selectively applying Kodak Poly-Toner (5:100 dilution). Eshbaugh tells us, “The fractured imagery reminds us of the limitations of the medium and the limitations of our own memories. We cannot capture a complete moment of time with a photograph, just as we can never remember a complete moment of time accurately. Each split pane exists in a paradox of harmony and conflict.”

Preparing Formulas

Weighing Chemicals

Place your scale on a level surface, protected from spills with newspaper or plastic, and zero it. Put a piece of filter paper, any clean paper, or a paper cup in the middle of the balance pan. For critical measurements with a triple-beam scale, weigh the paper or cup first and include its weight plus that of the chemical. On electronic scales this procedure can be done automatically by pressing the Tare button after the paper or cup is placed on the scale and before the chemical is added. When using a double-pan scale, place the same size paper in both pans so their weights will cancel each other out. Line up the needed chemicals in an orderly fashion. Put the chemical to be measured in the center of the pan to avoid any leverage errors. Use fresh paper for each chemical to prevent contamination and facilitate cleanup Immediately recap the bottles to avoid confusion, spills, or contaminating one chemical with another.

Temperature

Closely follow the temperature recommendations given with each formula. If the chemicals need to be heated, carry out this procedure in a double boiler, not in a pan directly over the heat source. Direct heat can alter or damage a chemical. The solubility of many chemicals is increased with heat. For this reason, the mixing temperature of the water may vary from the solution's working temperature. Other chemicals may release heat when dissolved, creating an exothermic reaction, and need to be mixed in cool water. Endothermic chemicals absorb heat when mixed and may require hotter water for complete mixing.

Figure 5.4 Anderson made this photograph by combining digital and analog methods. She captured the image with a digital Nikon and used Photoshop to soften and blur it slight Y. She then created a digital color separation negative, producing a palladium (warm) negative and a cyanotype (cool) negative, and printed it using the Precision Digital Negative System. To make the final image, she mixed her own chemistry. For the palladium print, she followed the Na 2 method, in which the salt form of platinum serves to adjust the contrast, and for the cyanotype print she combined 2 parts 20 per cent ferric ammonium citrate solution A to 2 parts 8 per cent potassium ferricyanide solution B. Exploring this personal method helped serve as Anderson's coping mechanism while she photographed the aftermath of Hurricane Katrina in New Orleans.

Mixing Chemicals

Always follow the prescribed order of chemicals given in the formula, as any changes may prevent the solution from being properly mixed. Follow specific recommendations provided with the formula and guidelines in Box 5.2. In general, start with two-thirds to three-quarters of the total amount of water at the correct mixing temperature. While stirring vigorously, slowly pour the first properly measured chemical into the water, not allowing any chemical to settle at the bottom of the container. Wait until each chemical has been completely dissolved before adding the next one. When the correct sequence has been followed and all the chemicals are thoroughly mixed, cold water can be added to bring the solution to room temperature. If you are not confident of the purity of the water being used, mix all developers with distilled water.

Box 5.2 Chemical Mixing Guidelines

■ Protect your eyes with safety glasses and your hands with disposable chemical barrier gloves, which are available at medical supply stores.

■ When mixing an acid, always pour the acid into water. Do not pour water into an acid, as splattering can cause dangerous burns. Wear eye protection.

■ Use a funnel when pouring mixed solutions into bottles. Tightly secure the top and label the bottle with the name of the solution and the date. Most developers are good only for a few months after they have been mixed.

■ Keep a written record of what you do so that you can judge the results, which permits easy adjustment and customization of the formulas.

Percentage Solutions

In some formulas the amount of a chemical may be too small to be weighed accurately, so the amount is given as a percentage solution, or in terms of weight per volume. For photographic purposes, this can be simply stated as the number of grams of a chemical that are dissolved in 100 milliliters of water. For instance, a 5 per cent solution has 5 grams of a chemical dissolved in 100 milliliters of water. Regardless of the amount needed, the percentage (how many parts of the chemical to be mixed into 100 parts of water) is always the same.

When making a percentage solution, mix the chemical in less than the total volume of water required. After the chemical is dissolved, add the remaining water. For example, in preparing a 7 per cent solution, dissolve 7 grams of the chemical in about 75 milliliters of water. After mixing is complete, add more water so that the final volume is exactly 100 milliliters.

Formulas in Parts

Older photographic formulas were often given in parts. Parts can be converted into the equivalent number of grams and milliliters or ounces and fluid ounces. For instance, a formula calling for 10 parts of a chemical and 80 parts of water can be translated as calling for 10 grams of the chemical and 80 milliliters of water or 10 ounces of the chemical and 80 fluid ounces of water.

Ph Scale

Most photographic solutions have a definite pH (potential of hydrogen), which is a way to measure the acidity or alkalinity of a chemical. Acidity is measured by the number of hydrogen ions present while alkalinity is measured by the concentration of hydroxide ions in a solution. The scale runs from 1 to 14, with 7 being neutral. Pure distilled water has a pH of 7. Chemicals with a pH below 7 are considered to be acids. Chemicals with a pH above 7 are alkalis. The change of one whole increment in the pH scale indicates a tenfold change (plus or minus) in the intensity of the acid or alkaline reaction.

Figure 5.5 Wetzel's interest in mixing her own formulas and in the tactile aspects of photography led her to explore the nineteenth-century wet-plate process (see Chapter 10), which gave her more personal involvement and control in the photographic process. The portable darkroom in the trunk of her car allowed the artist to process the plate on location. For Wetzel, “this work focuses on the random thoughts and memories - real or constructed - that we bury in our mind, tuck away in boxes, forgetting about them until we stumble upon the sealed container and open the door thereby shedding light on the contents.”

All photographic processing solutions perform best within a specific pH range. For example, developers must be alkaline to work, stop baths must be acid, and fixers are normally neutral to slightly acid. The pH of most of the commonly used working solutions in today's photographic processes is between 5 and 9. The pH can be measured with pH test paper or with a pH meter. The paper is inexpensive but not very reliable. A pH meter, which is expensive, is required for accuracy. Fortunately, most black-and-white formulas do not require strict pH monitoring. Small changes produced by variations in pH usually do not cause irreparable visual defects. Most of these changes can be corrected during the printing of a negative. The use of distilled water will eliminate most difficulties in controlling pH as long as the chemicals are reliable and all procedures are correctly carried out.

Chemicals possessing either a high or low pH should be handled with care. Acids on the low end of the pH scale get progressively stronger. Acids can dehydrate the skin and, in high concentrations, produce burns. Highly alkaline substances, such as calcium hydroxide, can degrease the skin and cause burns.

Acetic acid is the most commonly used acid in photography. It is a relatively weak acid in its standard 28 per cent photographic dilution and does not react as vigorously as other acids, but it can cause tissue damage in a concentrated form.

Prolonged exposure to photographic chemicals can cause allergic reactions, cracking, dehydration, or discoloration of the skin. Allergic reactions tend to be cumulative. Therefore, when mixing or working with any concentrated chemicals, wear full protective gear.

US Customary Weights and Metric Equivalents

When preparing your own chemicals, you will probably encounter formulas given in both the US customary and metric systems. The scientific world has adopted the metric system, but the US at large has not followed suit. Older formulas in British publications use still another system called British Imperial Liquid Measurement. These systems are not compatible. Many older formulas may be written in only one system, so it is often necessary to translate from one system to the other. This can be accomplished quickly and accurately by using one of the online conversion sites, such as www.worldwide-metric.com/metcal.htm, which gives calculations of the metric system into the US customary system and vice versa for length, weight, pressure, volume, and temperature. Tables 5.3 and 5.4 provide commonly used equivalents.

Equivalent Imperial and Metric Measurements

Table 5.3 Solid Measures

US and Imperial Measures		Metric Measures
Ounces	Pounds	Grams
1		28
2		28
3½		100
4	¼	112
5		140
6		168
8	½	225
9		250
12	¼	340
16	1	450
18		500
20	¼	560
24	½	675
27		750
28	1 ¾	780
32	2	900
36	2¼	1000
40	2½	1100

Table 5.4 Liquid Measures

Fluid ounces	US	Imperial	Milliliters
¼	1 teaspoon	1 teaspoon	5
¼	2 teaspoons	1 dessertspoon	10
1	1 tablespoon	1 tablespoon	14
1	2 tablespoons	2 tablespoons	28
2	¼ cup	4 tablespoons	56
4	½ cup		110
5		¼ pint or 1 gill	140
6	¾ cup		170
8	1 cup		225
9			250
10	14 cups	½ pint	280
12	½ cups		340
15		¾ pint	420
16	2 cups		450
18	2¼ cups		500
20	2½ cups	1 pint	560
24	3 cups		675
25		14 pints	700
27	3½ cups		750
30	3 ¾ cups	½ pints	840
32	4 cups or		900
	1 quart
35		1 ¾ pints	980
36	4½ cups		1000

Figure 5.6 Sarachek's chemigram process (see Chapter 12) is cameraless: his main tools include photo paper, chemicals, photosensitive resist, and light. To create this image, Sarachek first applied the resist coating to the black-and-white photographic paper with nonstandard objects such as sticks or socks and then treated the photo paper with chemicals that affect the unprotected silver. The resulting image, which is reminiscent of calligraphy, is largely previsualized. Sarachek states, “As with an abstract painter making a gestural brush stroke, an element of chance is coupled with my control of the media. I believe this combination of control and chance energizes the final image.”

Resource Guide

Anchell, Stephen G. The Darkroom Cookbook, Fourth Edition. New York: Routledge, 2016.

Donofrio, Diane (Ed.). Photo Lab Index, Lifetime Edition. Dobbs Ferry, NY: Morgan & Morgan, 2001.

..................Content has been hidden....................

You can't read the all page of ebook, please click here login for view all page.

Table of Contents for
Formulas of One’S Own

Chapter 5
Formulas of One's Own

Prepared Formulas Or Mixing Your Own