From: Sandy King (sanking@clemson.edu)
Date: 04/18/03-07:39:20 AM Z
On reviewing my response to Chris on how the color of the pigment
affects sensitivity and contrast in carbon printing I found an error
in the last sentence, which should read, "the blue would print
fastest and with greater contrast, the brown slowest and with most
contrast, assuming all else equal."
Sandy
>Chris,
>
>In carbon printing the color of the pigment has a very big impact on
>both printing speed and contrast. In printing color carbon, for
>example, with yellow, magenta and cyan tissue one finds in practice
>that the yellow prints slower than magenta, and magenta in turn
>prints slower than cyan. Contrast is about the same with yellow and
>magenta, but much greater with cyan.
>
>I am absolutely certain that if I were to test tissues made with
>pigments in the order you indicated the blue would print fastest and
>with greater contrast, the brown slowest and with most contrast,
>assuming all else equal.
>
>Sandy King
>
>
>>Question:
>> What is everyone's opinion about this: "theoretically, the color of
>>the pigment does not affect the sensitivity of the emulsion since the action
>>of the light is on the sensitizer and the gum"....that the only way pigment
>>affects exposure is in its density of holding back light, either by how
>>concentrated it is used in the mix or by the inherent density of the pigment
>>itself (I suppose what we would term "covering power").
>> I guess I am asking this: do you gum or carbon printers always find in
>>practice blue exposes more quickly, and so on down the line in order like
>>this: from shortest to longest times in this order: blue, green, violet,
>>orange, black, red, yellow, brown.
>> Or is that not true?
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