Photoshop grayscale problem

Hi Everyone,

I know this isn't a Photoshop newsgroup, but I'm hoping that someone here
might have encountered a similar problem that I describe below when
trying to digitize a 4x5 black/white negative. Any Photoshop gurus --
HELP, please, if you can. I'm a relative Photoshop neophyte...

I took a black/white negative and scanned it on my Epson V-700 scanner. No
matter whether I scanned in 8-bit or 16-bit mode, when my scanned image
comes up in Photoshop, the sky brightness, which varies greatly over this
highly vignetted photographic image, shows definite brightness "steps" from
darker to brighter. This sky brightness range is very compressed compared
to the image's whole brightness range. In other words, there is black in
part of the image, and white in another part. The sky varies from one shade
of gray to a slightly brighter shade. And these "quantization steps" make
the resulting image look TERRIBLE (at least in the sky portion of the
image). What can I do about this? I'd rather not add noise, since the
image right now looks wonderfully smooth. Please help! I'm a relative
Photoshop neophyte...

Thanks,
Scott

On Mar 29, 10:30 pm, "Scott Speck" wrote:
Hi Everyone,

I know this isn't a Photoshop newsgroup, but I'm hoping that someone here
might have encountered a similar problem that I describe below when
trying to digitize a 4x5 black/white negative. Any Photoshop gurus --
HELP, please, if you can. I'm a relative Photoshop neophyte...

I took a black/white negative and scanned it on my Epson V-700 scanner. No
matter whether I scanned in 8-bit or 16-bit mode, when my scanned image
comes up in Photoshop, the sky brightness, which varies greatly over this
highly vignetted photographic image, shows definite brightness "steps" from
darker to brighter. This sky brightness range is very compressed compared
to the image's whole brightness range. In other words, there is black in
part of the image, and white in another part. The sky varies from one shade
of gray to a slightly brighter shade. And these "quantization steps" make
the resulting image look TERRIBLE (at least in the sky portion of the
image). What can I do about this? I'd rather not add noise, since the
image right now looks wonderfully smooth. Please help! I'm a relative
Photoshop neophyte...

Thanks,
Scott

Are you scanning it in color then converting it to black and white in
photoshop? It sounds like a moot point but you might what to try it. A
really good read on photoshop tips and tricks is "the photoshop book"
for digital photographers by scott kelby.

Earl

On Mar 29, 8:30 pm, "Scott Speck" wrote:
Hi Everyone,

I know this isn't a Photoshop newsgroup, but I'm hoping that someone here
might have encountered a similar problem that I describe below when
trying to digitize a 4x5 black/white negative. Any Photoshop gurus --
HELP, please, if you can. I'm a relative Photoshop neophyte...

I took a black/white negative and scanned it on my Epson V-700 scanner. No
matter whether I scanned in 8-bit or 16-bit mode, when my scanned image
comes up in Photoshop, the sky brightness, which varies greatly over this
highly vignetted photographic image, shows definite brightness "steps" from
darker to brighter. This sky brightness range is very compressed compared
to the image's whole brightness range. In other words, there is black in
part of the image, and white in another part. The sky varies from one shade
of gray to a slightly brighter shade. And these "quantization steps" make
the resulting image look TERRIBLE (at least in the sky portion of the
image). What can I do about this? I'd rather not add noise, since the
image right now looks wonderfully smooth. Please help! I'm a relative
Photoshop neophyte...

Thanks,
Scott

I scan thousands of medium format b/w negatives as part of my job
(electron microscope tech). If you could post a photo of your results
it might be really helpful in obtaining advice. Or email me and I
will look at what you are dealing with.

--
Nicko

Scott Speck wrote:
Hi Everyone,

I know this isn't a Photoshop newsgroup, but I'm hoping that someone here
might have encountered a similar problem that I describe below when
trying to digitize a 4x5 black/white negative. Any Photoshop gurus --
HELP, please, if you can. I'm a relative Photoshop neophyte...

I took a black/white negative and scanned it on my Epson V-700 scanner. No
matter whether I scanned in 8-bit or 16-bit mode, when my scanned image
comes up in Photoshop, the sky brightness, which varies greatly over this
highly vignetted photographic image, shows definite brightness "steps" from
darker to brighter. This sky brightness range is very compressed compared
to the image's whole brightness range. In other words, there is black in
part of the image, and white in another part. The sky varies from one shade
of gray to a slightly brighter shade. And these "quantization steps" make
the resulting image look TERRIBLE (at least in the sky portion of the
image). What can I do about this? I'd rather not add noise, since the
image right now looks wonderfully smooth. Please help! I'm a relative
Photoshop neophyte...

Thanks,
Scott

Check that Photoshop is not converting the image to 8-bit mode. Look at
Image\Mode - Grayscale should be ticked, and at the bottom of the
dropdown menu, 16-bit should be ticked.

Colin D.

--
Posted via a free Usenet account from http://www.teranews.com

On Mar 29, 10:30 pm, "Scott Speck" wrote:
Hi Everyone,

I know this isn't a Photoshop newsgroup, but I'm hoping that someone here
might have encountered a similar problem that I describe below when
trying to digitize a 4x5 black/white negative. Any Photoshop gurus --
HELP, please, if you can. I'm a relative Photoshop neophyte...

I took a black/white negative and scanned it on my Epson V-700 scanner. No
matter whether I scanned in 8-bit or 16-bit mode, when my scanned image
comes up in Photoshop, the sky brightness, which varies greatly over this
highly vignetted photographic image, shows definite brightness "steps" from
darker to brighter. This sky brightness range is very compressed compared
to the image's whole brightness range. In other words, there is black in
part of the image, and white in another part. The sky varies from one shade
of gray to a slightly brighter shade. And these "quantization steps" make
the resulting image look TERRIBLE (at least in the sky portion of the
image). What can I do about this? I'd rather not add noise, since the
image right now looks wonderfully smooth. Please help! I'm a relative
Photoshop neophyte...

Thanks,
Scott


Make sure you are in greyscale not black and white, the latter is a 2
bit conversion for text, and says what it means, black and white. But
you shouldn't have the 8 or 16 bit versions with B&W selected, unless
you are setting the bit depth and then the mode. I have done quite a
few 4x5 negs, greyscale and color on a V700 and never had that
problem. I don't like B&W negs scanned in color on this scanner, so I
have been scanning in 16 bit greyscale and the results have been
great. They print very well on my Cannon iPF5000.

Tom

On Mar 29, 8:30 pm, "Scott Speck" wrote:
Hi Everyone,

I know this isn't a Photoshop newsgroup, but I'm hoping that someone here
might have encountered a similar problem that I describe below when
trying to digitize a 4x5 black/white negative. Any Photoshop gurus --
HELP, please, if you can. I'm a relative Photoshop neophyte...

I took a black/white negative and scanned it on my Epson V-700 scanner. No
matter whether I scanned in 8-bit or 16-bit mode, when my scanned image
comes up in Photoshop, the sky brightness, which varies greatly over this
highly vignetted photographic image, shows definite brightness "steps" from
darker to brighter. This sky brightness range is very compressed compared
to the image's whole brightness range. In other words, there is black in
part of the image, and white in another part. The sky varies from one shade
of gray to a slightly brighter shade. And these "quantization steps" make
the resulting image look TERRIBLE (at least in the sky portion of the
image). What can I do about this? I'd rather not add noise, since the
image right now looks wonderfully smooth. Please help! I'm a relative
Photoshop neophyte...

Thanks,
Scott

I am not familiar with that scanner. Does it have a transparency/
negative scan function, or are you scanning it as a print (reflective
medium)?

Scanning negatives is a real problem for reasons to be explained
below. For this reason, scanners with a built-in negative scan
function contain special software. In addition to inverting the
tones, it also handles the dynamic range and strange contrasts

I am assuming you do not have a scanner with a light source in the
lid, but are using the white screen in the cover. Now, a good
negative already has a wide dynamic range. When scanning a
transparency using the white lid, the light passes through TWICE! The
already high dynamic range is again increased greatly!

This screws up the dynamic range processing (curves function) of the
normal print scanning software. If the scanner does not have a RAW
function, you need to seriously get into the scanner options and play
with the contrast and brightness settings.

Best is to use a scanner already set up for scanning transparencies
and negs (i.e, one with a light source in the cover.

Scott Speck wrote:

I took a black/white negative and scanned it on my Epson V-700 scanner. No
matter whether I scanned in 8-bit or 16-bit mode, when my scanned image
comes up in Photoshop, the sky brightness, which varies greatly over this
highly vignetted photographic image, shows definite brightness "steps" from
darker to brighter. This sky brightness range is very compressed compared
to the image's whole brightness range. In other words, there is black in
part of the image, and white in another part. The sky varies from one shade
of gray to a slightly brighter shade. And these "quantization steps" make
the resulting image look TERRIBLE (at least in the sky portion of the
image). What can I do about this? I'd rather not add noise, since the
image right now looks wonderfully smooth. Please help! I'm a relative
Photoshop neophyte...

Make sure you have the auto controls off on the scanner. Set the manual
controls carefully.

Scan in 16 bit.

And then hope. It may well be that the maximum density of these
negatives (which, remember, is the area representing the *brightest*
parts of the scene; they're *negatives*) is down near or beyond the
limits of that scanner. Flatbed scanners don't do the best jobs on
film, especially slides and B&W negs, for this among other reasons.

And good luck.

(The term for what you're seeing is "posterization", if I'm
understanding your description correctly.)

Make sure your monitor isn't set for 256 colors or 16-bit color. You want to
use 24-bit or 32-bit color for your monitor color settings. Especially when
working with Photos.

=(8)