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10.1 – Photographic Paper
No matter how carefully the photographer worked to produce an excellent negative, the final result depends on the paper used. Papers all have different characteristics but basically they all have a light sensitive coating and a paper support. The chemical composition of the silver salt, method of its formation and any special agents will determine its characteristics (speed, contrast and image tone). A black and white print is merely a range of tones or densities that represent the light and shade of the original scene.
Emulsions
Most emulsions are made from light sensitive silver salts called silver halides, which are suspended in gelatin. Silver chloride (contact paper) and silver bromide (enlarging papers) are the silver salts, which are most commonly used. Speed of paper is not only dependent on salt but on manufacturing methods. For instance silver halides only absorb blue, however by the use of certain sensitizing dyes it can become sensitive to the whole spectrum. However to show how speeds vary, Grade 2 contact paper has a paper speed of 8 whereas Grade 2 enlarging paper has a speed of 500. As paper is exposed to more and more light it will produce more and more density up to a certain point and then the paper cannot become more dense. The method of rating a paper's sensitivity is called a sensitometric curve. The whole study of sensitometry will be discussed in a later lesson.
Contrast Grade
The term contrast can mean subject lighting, the negative, and development. The paper grade or contrast is extremely important to the photographer. Different papers will vary in contrast usually the higher the grade the more the exposure. However one kind of paper, medalist, has the same exposure time for all grades. The density range of a negative is the difference between the highest and lowest densities. The log exposure range is defined as the relationship between the exposure needed to give maximum highlight detail and the exposure needed to give the maximum shadow detail. The grade numbers of paper will each vary for the log exposure.
The grades of paper vary from 0-6. However most manufacturers just make 1-5. Grade 1 is a soft paper and would be used with an extremely hard or contrasty negative. Grade 5 paper is a hard paper and would be used with a soft or flat negative. Normal paper is most commonly grade 2. Polycontrast paper comes in one grade for all contrasts. In order to save on having a lot of different boxes of graded paper available, this kind of paper can be used. Rather than using different papers for various contrasts, filters are used with the same to achieve different contrasts. Before purchasing any kind of paper be sure that the paper will not be ruined (fogged) by the wrong safelights. Polycontrast paper is more expensive than graded paper however one paper does all. It will work with a color enlarger. The various color filters can be used to achieve the different contrast grades. Graded paper has more contrast than Polycontrast paper.
Base
All photographic papers are made from wood pulps. The two kinds of paper bases are fiber base and resin-coated. Fiber base is the traditional type of paper base. Processing times are longer because the papers will absorb the chemicals. The other base is resin-coated (RC) which has a plastic sheet on the back to make it water-resistant. RC paper costs a little more but the time saved in processing and drying may be worth the expense.
Weight
Lightweight (LW)-This paper is a thin or lightweight stock and is intended for photographs that are to be folded or used on documents such as passports. Part of the weight and stiffness of photographic papers is caused by the baryta coating which increases the reflecting power of the paper. This coating is not applied to LW paper. Lightweight paper is also called document weight.
Single Weight (SW)-Single weight paper is relatively thin. It is about half as thick as double weight stock. It is used for all ordinary photographic purposes. These papers may be processed more rapidly. They are less bulky than double weight paper. Single weight papers are best suited for print sizes 8x10 and smaller also for larger prints that have to be mounted. Most all of the common glossy surface prints are on single weight papers.
Medium Weight (MW)-This paper was made popular for people who prefer heavier paper but can not afford double weight paper.
Double Weight (DW)-This paper is thicker than the average heavy postcard. It is the heaviest stock normally used. However, there are emulsions supplied on a cardboard-weight base for making postcard prints. Double weight papers generally used for large prints because they stand up better under rough treatment. Heavy papers are also recommended for portrait and exhibition photographs. Double weight papers have several different surface textures, which will be discussed later.
Texture
Paper comes in textures such as smooth, fine grained, tweed, silk and tapestry.
Brilliance
This is the final surface of a sheet of photographic paper. The various shades of brilliance are: glossy, high lustre, lustre, and matte.
Glossy- Practically all of the light is reflected from the glossy surface which give maximum detail and brilliance. Glossy paper has two or more coatings of hardened gelatin applied to the surface. This glossy paper can be dried naturally, giving it a semigloss effect or a highly polished surface can produce a high gloss. The requirements of publication photographs places emphasis on maximum detail and brilliance. These factors are best achieved with smooth glossy white papers.
High Lustre & Lustre-This coating is for the photographer who prefers a finish which is semi-matte. This finish does not have the shine of glossy but more brilliance than matte. The lustre paper will have less tonal shades than glossy more shades than matte.
Matte-The reflected light from matte surfaces is almost completely diffused. These softer less glaring surfaces are preferred for pictorials, portraits and landscapes. The rougher papers have a noticeable texture, which may vary from a lightly pebbled effect to a fabric like texture that may resemble linen or a very rough tweed. The rougher surfaces subdue fine detail in proportion to the degree of roughness. This emulsion is useful for prints that do not depend upon detail for interest.
Tone
There are four various tones of photographic papers. They are blue-black, neutral-black, warm black, and brown black. There are two categories of tones, they are warm tone and cold tone. The blue-black and neutral-black are cold tone papers. The cold tone papers tend to be bluish. Warm tone papers are brownish. The warm-black and brown-black are warm tone papers.
Tint
The tint of paper bases is usually added to the baryta coating, which is applied to most papers before the emulsion coating process. In addition to the common white papers, there is bases slightly tinted cream, ivory, warm white, buff, and a few are tinted with stronger colors.
Subjects having cold colors and prints to be copied usually require a white paper stock. Portraits, landscapes, and sunshine effects are usually much richer with the added warmth of a cream white. Buff-colored papers are preferred by many for portraits of elderly people.
Surfaces (Kodak)
All companies furnish various surfaces. These surfaces come in different letters. For example: A, E, F, G, J, K, M, N, R, X, and Y. The surfaces consist of weight, texture, brilliance, tone and tint. However many companies will make various alterations of the different surfaces.
Sizes
Paper is available in rolls and sheets. Most all paper is rectangular. The common sizes are 4x5, 5x7, 8x10, 11,x14 and 16x20. The size of the paper should be determined by the size of the negatives. For example a square negative (like the instamatic) should be printed on a square sheet of paper.
Test Strips--Why
Because the exposing light source may vary in "strength", and because each negative is different in regards to its tone range, it is impossible to establish a definite exposure time for either a contact print or enlargement. It is necessary to make "test strips" to establish the correct exposure time and thusly saves the cost of a full sheet of paper.
Test strips are not valid if used under any of the following conditions:
In other words, a test strip is valid for the time at which it is made and is not valid if you change paper grades, negatives, development time, temperature, enlargers, chemical strength, or aperture setting.
MATCHING PAPER AND NEGATIVES
If a group of negatives were held up to a light and you looked through them, you would observe that they would differ in the number of tones each contains. Some negatives are dark, some are light, others look to be sort of "muddy" or gray in cast, while others show only light and dark areas.
Negatives are judged or rated according to contrast. The definition of contrast is the difference between the lightest or clearest area and the darkest area. A negative with good contrast will have light areas, definite gray areas, and black areas. Regardless of their first appearance, most negatives can be classified into three broad categories--flat, normal and contrasty. The easiest way to do this classifying is to categorize them in relationship to the "tonal balance" they have. A negative is said to have good contrast if you can read printing through the black areas of the negative.
Normal Negative
If a negative were perfect, it would contain 128 tones. This is assuming that the equipment was available to measure all the different ones. The perfect negative would be a normal negative. It would contain transparent (white) areas, many gray areas and some dark (black) areas. On a linear scale, a normal negative would be represented by tones ranging from opaque to transparent.
Flat Negatives
If a negative appeared to have a few tones, or contained mainly one tone, it would be called a flat negative. Flat negatives can be sub-divided into two categories--thin flat and dense flat. A thin flat negative is transparent, or almost so.
A dense flat negative would have the tones at the opposite end of the tone scale. The tones would appear mostly dark gray or black.
Contrasty Negative
A contrasty negative has all the middle tones missing and as a result there is too much contrast between the different tones of the negative. The tones are either black or white.
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Opaque Tones |
Middle Gray Tones |
Transparent Tones |
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These classifications are broad, as there are some types of negatives that would conceivably fit into two categories. This is possible because no two people can visualize a "border line" negative and agree 100 per cent as to its classification. Theoretically, there should be 128 categories, but this is not practical.
Paper Grades
Whether enlarging or contact printing, the light sensitive paper is supplied in different "grades" which generally range from #1 to #4. Each number represents a different emulsion contrast. The higher the number the more contrasty the emulsion. This now brings us to the problem of how to get a good print from any negative by using different grades of paper. As a general rule paper and negative can be matched as follows in order to obtain a "normal" print. The following statements are very important--please commit them to memory.
Use #4 paper with a flat negative (either thin or dense)
Use #2 or #3 paper with a normal negative
Use #1 paper with a contrasty negative
If you were to draw a linear scale for the sensitivity of each of the paper grades, it would appear as follows:
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Opaque Tones |
Middle Gray Tones |
Transparent Tones |
The best paper grade to use is #2 or #3. Any time grade #1 or #4 has to be used to make a negative render a normal print some tones are lost.
If the wrong grade is used with a negative, the results could be disastrous. An example would be if a negative was flat and you chose the wrong paper grade, #1, the results would be a very flat print. Please observe the following chart:
