[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Digital Negatives with enough Tones for Pt/Pd
Maybe we should put an end to this one. After having thought this through,
once again, I realized that the number of bits being sent to Photoshop by
the scanner is really not the culprit here - the culprit is the printer, its
algorithms or the medium upon which the image is printed and I shall explain
why it is not 8 bits per se.
First I want to clarify some related info for the uninitiated - this has
been a source of unclear info in this thread.
Some may not understand the relationship between 8 bits and 24 bits (called
"True Color" by most video card manufactures) versus 12 bits and 36 bits
versus 16 bits and 48 bits - this is simply 3 colors times the number of
bits being presented. Three colors at 8 bits = 16+ Million colors
(256X256X256) Most scanners made today scan at 12 bits or more. Some can
actually save the file independently of Photoshop at a bit depth greater
than 8 and Photoshop can open those files at the native bit depth up to 16.
Photoshop can not apparently (?) recieve a file directly from a scanner at a
bit depth greater than 8 bits (per color). The problem is that when you
render this image to a grayscale the color channels are reduced to one and
the number of colors is reduced to 256, which is what Jeffrey is complaining
about and what I believe the printer can't handle properly.
That being said, I must relate an observation that pertains to an an 8 bit
Photoshop file that produces posterization in the highlights when the
negative for Pt/Pd is printed on an inkjet printer (not all my 8 bit images
do so). I have also sent this same image (exactly the same file) out to a
Lightjet lab and the resulting Pt/Pd prints appear continuous in almost
every respect. The differences do not relate to colors or posterization but
to the number of lines per inch generated by the Lightjet dependent upon
resolution - but this is not the issue here.
There may be something to gain by adopting the hypothesis conveyed at the
beginning of this thread and one might be successful in utilizing the custom
procedure that develops, but, is it worth the effort?