Quote:
Originally Posted by Chris
I appreciate that a tiff is lossless on successive saves, but does it retain everything there was in the RAW?
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Quote:
Originally Posted by Roy C
Yes I believe it does Chris.
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Roy - Chris is right to question this because this is definitely NOT the case. ANY edit in PS modifies pixel values and therefore destroys information. I appreciate that if you work with layers that is not destructive editing and you can return to the original, but when you flatten the image for web or print it you are then taking the modified values. In contrast editing in RAW does not. You should do as much editing in RAW as possible and then switch to PS for edits that can not be carried out in your RAW processor eg selective edits, althhough I believe that LR in V2 now has some selective processing capability.
By way of an example here are three version of an image that I took the lake district a few weeks ago. This is deliberately underexposed as part of a bracketed series but it serves to show the difference between processing in RAW and PS. Obviously with correctly exposed images, the effects are less exederated, but will still be there.
Image 1 is the as shot RAW converted to 16bit with no adjustments and then resized and converted to JPG
Image 2 is the above image with a curves adjustment added in PS.
Image 3 is the RAW image with exposure, fill light & black level adjustments in LR and then converted to 16bit and the resized and converted to JPG.
In each case I have superimposed the histogram in the corner. Note in images 1 & 3 the histogram is continuous, were as in image 2 there are large gaps - denoting the complete absence of pixels with that value, the net result being loss of tonal range & shadow detail in particular, which is visible in the shadows on the hills.
To lean how to get to grips with the LR/PS RAW converter interface try either of these books: -
Real World Camera RAW by Bruce Fraser
Photoshop Lightroom by Martin Evening
Its worth the effort
