Gray Scale vs RGB (Part 1: Origin) © 2016

Yesterday I gave a talk at Middlesex County College in Edison, NJ to students in a History of Photography class.  In discussing my workflow I was explaining the curves I apply when making my digital negatives and how I used to print out my negatives in Gray Scale mode until I recently embarked on a test to create Gum over Van Dyke prints (subject of my last blog post).  Normally when I make the color separated negatives for my full color gum prints, I print the negatives in Gray Scale mode since Photoshop automatically converts the RGB image into Gray Scale after you “Split Channels” in “Multichannel” mode. However, since I was using a single negative for the Gum over Van Dyke test, I decided to “Desaturate” the color in the original image rather than changing from RGB to Scale Mode (which discards the color information) before inverting the image and applying my curve. For comparison, I also created a negative where I converted the original image from RGB to Gray Scale mode.  The results below show the Gray Scale negative on the left and the RGB negative on the right.  


The RGB negative on the right shows more detail and tonal definition than the Gray Scale counterpart on the left.  I made Van Dyke prints to see how the negatives would translate differently. The print on the left below is made with the Gray Scale negative and the print on the right is made with the RGB negative.


Not surprisingly, the Van Dyke print made with the Gray Scale negative is flat and lacks shadow detail whereas the Van Dyke print made with the RGB negative has more contrast and detail. The results were extremely promising and I was eager to try making my full color gum prints now using RGB negatives instead of Gray Scale negatives—which will be the subject of my next blog post.

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