July 25, 2007
Do Curves Throw You a Curve?
Source: Luminous Landscape
Author: Mark Segal
The Luminous Landscape website has posted an essay by Mark Segal, who is a member of the Applied Color Theory List (ACTL), on the subject of Adobe Camera Raw (ACR) tone curves. This essay offers a detailed analysis of how the tone curve adjustments that you can apply in Camera Raw or Lightroom compare to the traditional approach of using RGB composite curve adjustments in Photoshop. Over on the ACTL list, Dan Margulis has suggested that it is better to use Camera Raw adjustments to make minor corrections only and use Photoshop Curve adjustments to make the major tone edits. Dan has also argued that in some cases ‘opening the range in Camera Raw actually damaged the image to the point where it was no longer possible to get a good result without excessive effort…’ In response to this claim, Mark has tested his own hypothesis, which is that Camera Raw adjustments applied to a raw capture in Photoshop ACR or Lightroom are not any more destructive than Photoshop and if anything, tone and color edits are easier to make in ACR, but Photoshop edits are still very useful for minor tone and color edits on a rendered raw image.
To access the PDF document and join the discussion you will need to read the full story on the Luminous Landscape website.
Since the appearance of Adobe Photoshop Lightroom, Adobe Photoshop CS3 Beta with Camera Raw, then CS3 with Camera Raw 4.x people have been asking about where best to implement luminosity and colour adjustments. Lively discussion of this matter occurred most recently on this website’s Forum, and since before that on the Applied Color Theory List (ACTL), a Yahoo membership group run by Dan Margulis.
Mark Segal, a member of ACTL. and contributor to this website, was an early adopter of the new software products and has printed a large number of images from his raw files processed using CS3 and Camera Raw 4 in both Beta and commercial versions. Much of the recent discussions have focused on the question of using Curves and other luminosity adjustment tools in Camera Raw 4 and Photoshop.
Based on his experience using these applications, Mark found a number of positions taken in these discussions surprising, and decided to test the various arguments. He thought the results of this work sufficiently interesting to write-up and share with others. While a large amount of very good material already exists on how to use the new tools, the particular interest of this article lies in the comparisons it makes between them, and in the ways it explores the interactions between contrast and saturation and how these interactions are controlled, whether in Camera Raw or in Photoshop.