Basic Photography Course

rapidly enough to cause boiling or a splashing explosion
that may splash the solution on someone nearby. Acids

should always be poured slowly into a solution (near the
edge of the container) while rapidly but carefully stirring
the liquid.

LABELS

Mixing tanks, storage tanks, and machine tanks for

developer, stop bath, fixer, and other solutions must be
labeled clearly with waterproof tape or nameplates to
reduce the chance of putting a solution into the wrong
tank. The label should contain the name of the solution,
the date it was mixed, and the name of the person that
mixed it. It is also mandatory that hazardous chemical
labels be attached to all chemical containers.

CONTAMINATION

All of the mixing equipment and the mixing area

must be cleaned immediately after use to prevent
solution contamination. The mixing tools and tanks
must be thoroughly cleaned right after use to prevent
dried solutions from forming encrustations that could
dissolve when a new solution is mixed. Mixing tools that
have not been used in some time should be washed
before use to remove any dust or dirt that may have
accumulated.

PREPARATION OF PHOTOGRAPHIC

SOLUTIONS

When mixing photo chemicals, you should always

start with clean tools and a clean tank with the right
amount of water-usually about one half to three fourths

of the final volume. The temperature of the water must
be as specified in the instructions. Developers are
generally mixed at or about 90°F to 125°F, while fixers
are mixed in water that should not be much above 80°F.

Always dissolve or dilute ingredients in the order

called for by the instructions. Dry ingredients must be
completely dissolved before the next ingredient is
added. All liquids must be completely diluted, while
stirring, before the next ingredient is added.

After a liquid is added to a solution, rinse the bottle

and add the rinse water to the solution, so all the

concentrated liquid is used.

After all ingredients have been combined and

thoroughly dissolved, diluted, and mixed, water should
be added to bring the solution up to the correct volume.
Do not forget to mix this water thoroughly into the
solution.

FOLLOW DIRECTIONS

Before mixing photographic chemicals, you should

read the manufacturer's directions carefully. Much
research goes into the production of chemical products;
however, it is only effective when the chemical is mixed

and used properly. The directions for even the most
familiar product should be reviewed, because there are
continual attempts to improve photographic materials;
for example, new film or developer combinations may
call for changes in dilution, processing time, or
temperature to get the required results. Learn to follow
directions. This is very important in the preparation of
chemicals for both quality and safety reasons.

Remember to follow the proper procedures for

chemical safety. You should prepare the chemicals in a

well-lighted and well-ventilated room. Do not taste or
inhale any chemical. You are required to wear rubber
gloves, a rubber apron, eye protection, a long sleeve
shirt, and a respirator for your personal protection.
Remember, for safe mixing and quality results,
FOLLOW DIRECTIONS.

CAUTION

In most imaging facilities, it is common

practice to connect a hose to the water spigot to
aid in filling a chemical mixing tank and to
prevent splashing in the sink. Aboard ship,
hoses attached to potable water spigots can back
siphon chemicals from the tank or sink into the
drinking water supply. Such hoses should either
be removed after each use or have a backflow
preventor installed in the plumbing system.

CHANGING PERCENTAGES

You must know how to prepare percentage solutions

from liquid chemicals. When the chemical on hand is in

liquid form and of known strength, a percentage solution
can easily be prepared by the following method:

Amount Wanted x Strength Desired

Strength on Hand

Multiply the amount wanted by the strength desired

and divide the product by the strength of the chemical

on hand; for example, you need 11 ounces of 28 percent

acetic acid. The chemical on hand is glacial acetic acid,

99.5 percent. Thus,

11 x 28

308

99.5

= 99.5 = 3.09 = 3 ounces

9-9

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Basic Photography Course

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DOFMaster for Windows On-line Depth of Field Calculator DOFMaster for Mobile Devices On-line Depth of Field Table Hyperfocal Distance Chart Articles FAQ Recommended Books Support Contact Links Home As an Amazon Associate I earn from qualifying purchases.	contents <- previous page next page -> rapidly enough to cause boiling or a splashing explosion that may splash the solution on someone nearby. Acids should always be poured slowly into a solution (near the edge of the container) while rapidly but carefully stirring the liquid. LABELS Mixing tanks, storage tanks, and machine tanks for developer, stop bath, fixer, and other solutions must be labeled clearly with waterproof tape or nameplates to reduce the chance of putting a solution into the wrong tank. The label should contain the name of the solution, the date it was mixed, and the name of the person that mixed it. It is also mandatory that hazardous chemical labels be attached to all chemical containers. CONTAMINATION All of the mixing equipment and the mixing area must be cleaned immediately after use to prevent solution contamination. The mixing tools and tanks must be thoroughly cleaned right after use to prevent dried solutions from forming encrustations that could dissolve when a new solution is mixed. Mixing tools that have not been used in some time should be washed before use to remove any dust or dirt that may have accumulated. PREPARATION OF PHOTOGRAPHIC SOLUTIONS When mixing photo chemicals, you should always start with clean tools and a clean tank with the right amount of water-usually about one half to three fourths of the final volume. The temperature of the water must be as specified in the instructions. Developers are generally mixed at or about 90°F to 125°F, while fixers are mixed in water that should not be much above 80°F. Always dissolve or dilute ingredients in the order called for by the instructions. Dry ingredients must be completely dissolved before the next ingredient is added. All liquids must be completely diluted, while stirring, before the next ingredient is added. After a liquid is added to a solution, rinse the bottle and add the rinse water to the solution, so all the concentrated liquid is used. After all ingredients have been combined and thoroughly dissolved, diluted, and mixed, water should be added to bring the solution up to the correct volume. Do not forget to mix this water thoroughly into the solution. FOLLOW DIRECTIONS Before mixing photographic chemicals, you should read the manufacturer's directions carefully. Much research goes into the production of chemical products; however, it is only effective when the chemical is mixed and used properly. The directions for even the most familiar product should be reviewed, because there are continual attempts to improve photographic materials; for example, new film or developer combinations may call for changes in dilution, processing time, or temperature to get the required results. Learn to follow directions. This is very important in the preparation of chemicals for both quality and safety reasons. Remember to follow the proper procedures for chemical safety. You should prepare the chemicals in a well-lighted and well-ventilated room. Do not taste or inhale any chemical. You are required to wear rubber gloves, a rubber apron, eye protection, a long sleeve shirt, and a respirator for your personal protection. Remember, for safe mixing and quality results, FOLLOW DIRECTIONS. CAUTION In most imaging facilities, it is common practice to connect a hose to the water spigot to aid in filling a chemical mixing tank and to prevent splashing in the sink. Aboard ship, hoses attached to potable water spigots can back siphon chemicals from the tank or sink into the drinking water supply. Such hoses should either be removed after each use or have a backflow preventor installed in the plumbing system. CHANGING PERCENTAGES You must know how to prepare percentage solutions from liquid chemicals. When the chemical on hand is in liquid form and of known strength, a percentage solution can easily be prepared by the following method: Amount Wanted x Strength Desired Strength on Hand Multiply the amount wanted by the strength desired and divide the product by the strength of the chemical on hand; for example, you need 11 ounces of 28 percent acetic acid. The chemical on hand is glacial acetic acid, 99.5 percent. Thus, 11 x 28 308 99.5 = 99.5 = 3.09 = 3 ounces 9-9 contents Basic Photography Course <- previous page next page ->	As an Amazon Associate I earn from qualifying purchases.
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