Digital BW, The Print

Bernd,

To give you some idea of how bad a histogram can look and still 
provide a good print I have uploaded an image of three histograms to 
the "Files" section of the Group Homepage in the "Message Related 
Files" folder entitled "Barracks Photo Histograms"

These are from two photos in the "Photo" section of the homepage that 
I uploaded to illustrate message #17.

The first histogram is of the 8-bit grayscale tiff file (Barracks 1) 
made on a drum scanner by a service bureau. Not the greatest, as you 
can see, and leaving me with a lot of adjustment to do. (Yes I did 
ask them to redo the scan. This was their third attempt and the best 
of the three.)

The middle histogram is of the entire flattened file (Barracks 2) 
after all adjustments were made to achieve the final image. There are 
lots of gaps and spikes.

The last histogram is of just the sky portion of the image after 
final adjustment. Not much left.

The histograms say this image should not print but it does. The image 
is at the limit. If I try to push it any farther the sky begins to 
posterize. If I was in 16-bit I could push it farther.

My point is that the histogram is a guide to check during image 
adjustment but all that really matters is the print. So make the 
adjustments you need to achieve what you want and see if it will 
print. Don't give up on an adjustment just because the histogram 
looks poor or even terrible.

Martin



--- In DigitalBlackandWhiteThePrint@y..., ruhrfoto@y... wrote:
> Fellows,
> 
> if I open an image file in PS 5.5 or 6.01, which I saved in 8 bit 
> grayscale modus before and proced only a little curve tweaking, 
> for instance elevating the 3/4 tones by 3% and lowering the 1/4 
> tones by 3% in order to get a little more contrast 
> (image/adjust/curves) I always heavily destroy my histogram. 
> That means multiple levels count zero while others count 
> doubled values compared to their neighbours.
> That never happens if I do the same adjustments in a 16 bit 
> greyscale file.
> Switching back from 8 bit to 16 bit doesn´t help.
> Is that normal, or did I miss something.
> Thanks for your advise.
> Bernd
> 
> PS 
> I use to scan in 16 bit greyscale or 48 bit RGB, but I save my 
> "ready to print files" in 8 bit, so if I want to change them later 
I 
> must handle the 8 bit file.