Funderburk, Kit. A Guide to the Surface Characteristics: Kodak Fiber Based Black and White Papers. (Second edition)/Chapter 5: Can a difference be seen? Can a difference be measured? Does it make a difference?
From George Eastman House : Notes On Photographs
 Table of Contents / Acknowledgements /Introduction / Chapter 1: Kodak Alphabet Soup: What's in a name? / Chapter 2.1: Papermaking for B&W Papers / Chapter 2.2: Papermaking for B&W Papers / Chapter 3: Baryta Coating for B&W Papers / Chapter 4: Making the Fiber Base B&W Surfaces / Chapter 5: Can a difference be seen? Can a difference be measured? Does it make a difference? |
| © 2009 Kit Funderburk Reproduced by permission of author |
Modern quantitative methods provide the ability to analyze fiber base B&W papers and there are many different interests in furthering the capability to characterize these papers. The characteristics of Kodak papers were not always strictly defined so caution is necessary in interpreting current analytical data.
It has already been discussed how the classification of weight (Double Weight, Single Weight, etc) was based on ranges of raw base weights and did not account for the weight of subsequent baryta coating layers. Not all Double Weight papers, for instance, were intended to be the same weight, nor the same thickness, and the weights and thicknesses changed over time and sometimes independently.
Like weight classifications, descriptions used for texture, gloss, and tint were also not precise. The comments below are offered to provide some background on “differences” that might be expected to show up under analytical analysis.
Texture
The first edition (1940) of the Kodak Reference Handbook referred to the “character” of the texture and described that character according to visual appearance and impact on the intended use of the photographic print.
The seven different textures used as the baseline in this guide were visually distinctive and the character of each texture was relatively consistent from at least the 1940s to its discontinuance. Therefore, one of these specific textures would not generally be mistaken for one of the other six textures.
This does not hold, however, for some of the textures of the early 1900s. As pointed out in Chapter 4, the early papers identified as either Smooth or Rough textured were sometimes not consistent in visual appearance and, in at least one case, a Rough paper appeared to have a smoother surface than a Smooth texture paper and neither would be considered to be a smooth paper by later standards.
While a Smooth / Glossy paper is relatively easy to identify, a Smooth texture with another level of sheen (for example, Semi-matte or Matte) can be mistaken for a different texture. The Velvet texture can also be difficult to identify since it is only slightly less smooth than Smooth textures of its time.
It is important to clarify that the visual nature of the character was apparent under normal viewing. It was not necessary to magnify or enlarge the texture detail in order to observe the differences. In fact, enlargement tends to mask the character of the rougher textures (Tweed, Tapestry) and high magnification can make the Smooth textures appear to have surface irregularities. Low magnification of the embossed textures does clearly reveal the pattern of the texture but magnification is not required to see that it is a unique surface.
Does this mean that any particular texture, measured today by modern analytical equipment, would be found to be identical to samples from, say, different years? Absolutely not! It is highly likely that measurement differences would be found as a result of manufacturing variability and as well as texture differences due to different raw base weights. For example, the depth of the Tweed texture on a Single Weight paper would have been slightly different than on a Double Weight paper due to compressibility differences during the felt marking process. But Single Weight Tweed and Double Weight Tweed both had the same character and both would have been recognizable as Tweed. In instances noted where a particular texture might have been adjusted to meet a specific customer demand, the change would have been visually subtle.
Sheen
While the character of the texture did not change (with the exception of some of the early Smooth and Rough papers), the sheen descriptions appeared to have been more often based on a relative positioning compared to other surfaces offered at the same time than on an absolute level of reflectance. At any given time, it was apparent that the hierarchy from highest sheen (highest surface reflection) to lowest sheen was as follows:
- Glossy
- High Lustre
- Lustre
- Semi-matte
- Matte
However, all grades identified with the same sheen description did not always have the same visual appearance and would not have the same measured sheen if analyzed today. For example, in the 1952 Kodak Professional Handbook, a sample of Rough / Lustre paper had higher visual surface reflection than did a sample of Tweed / Lustre. An even greater difference was apparent in 1963 samples in which Silk / Lustre had much higher visual sheen than did Tapestry / Lustre.
Besides the impacts on surface reflection and the maximum photographic density, the sheen also influenced the perception of texture. In the case of Fine-grained texture, the apparent depth of the texture appeared to be greater on High Lustre papers than on Lustre papers. However, manufacturing records show that the texture was not different as the same support was used for both High Lustre and Lustre products.
Tint
Tint descriptions appeared to have had more to do with describing the impact on the tone of the final print than on describing an exact color of the support. Based on samples in the guide books, it was obvious, for example, that all products identified as White were not visually identical. What White papers had in common was a blue-white (cold) appearance but the formulas for “white” papers were not all the same and those differences were recognizable even before instruments were available to assign a precise color measurement. An example can be seen in the table in the Tint section of Chapter 4 which showed that one raw base was coated with 4 differently tinted baryta formulas yet all were in the general classification of White tinted.
Like other surface characteristics, the Tint categories represented visual differences. Some of those differences can best be assessed by a side-by-side evaluation. While White would not be confused with Old Ivory, the difference between White and Natural is sometimes difficult to see especially if the samples are old. The difference between Cream White and Old Ivory can usually be identified in side-by-side comparisons but as a single stimulus each can be mistaken for the other especially in older samples that have faded.