32 band grey?

[juliewood]

I've seen a couple references to using a 32 band grey technique which sounds very useful, but searching through the forums and tutorials I can't find an explanation. Can anyone please point me in the right direction? Thank you!

[skoobey]

Re: 32 band grey?

What is that???

32 bit? Maybe? It's not a technique, it's an image depth.

[insmac]

Re: 32 band grey?

Never heard of it.

[Tony W]

Re: 32 band grey?

Any chance you could point to the references or the context of such a technique being useful?

Not a clue really and the closest I can imagine is posterisation of an image to 32 levels, but cannot imagine if that was the case what you would do with it.

[AKMac]

Re: 32 band grey?

32bit Grayscale?

[AKMac]

Re: 32 band grey?

32 bit HDR?

[skoobey]

Re: 32 band grey?

Is it a bird? Is it a plane?

[Aladdin]

Re: 32 band grey?

I know of a 32 step gray card to calibrate the monitor before the days of hardware based monitor calibration.

If you are able to distinguish among the 32 levels of the gray card (image), then the brightness and contrast on your monitor are correct.

It was useful way to make sure that the monitor is setup correctly.

Back then, some photo centric sites had a gray scale band either on the top or bottom of the opening page for users to validate that their monitor was set correctly to be able to view the pictures correctly.

Sounds like 32 shades of gray

[andrewrodney]

Re: 32 band grey?

I know of a 32 step gray card to calibrate the monitor before the days of hardware based monitor calibration.
If you are able to distinguish among the 32 levels of the gray card (image), then the brightness and contrast on your monitor are correct

Not necessarily (we can go there if you want).

[juliewood]

Re: 32 band grey?

I will look for the original references again. It sounded like they had split the luminosity of the image out into the 32 steps of the gray card Aladdin referenced. One person mentioned a way to fix blemishes or restoration spots that involved selecting the level (channel?) they were on and lightening it until the blemishes matched the surrounding grays. The other reference was along the lines of "a retoucher's toolbox includes dodge&burn, frequency separations, noise reduction, 32 band gray, degrunge, etc." I believe both posters were Senior Member level so I thought "oh, this must be a common thing I just haven't heard of yet."

Just realized, I wonder if search knows that gray=grey. That may be why I can't find it. I will report back. Now it's a quest!

[juliewood]

Re: 32 band grey?

Ok, it's a little frustrating because search ignores 32 but I did find one of the references, by Kraellin in 2006:

"curves, contrast/brightness, levels, lum frequencies, 32 band gray, clarify, high pass sharpen, and noise reducers are going to be your next steps. these are almost all tools that will tend to bring out detail by using contrasting methods. in other words, you're going to sharpen by contrast. you can also use blending modes with layers. you do one tool, make a duplicate and test some blend modes between those layers. this will often give you a bit more detail as well."

http://www.retouchpro.com/forums/image-help/13531-1950s-kodacolor-gone-mad.html#post121739

In the same thread, also by Kraellin:

"for cleaning up his pants and shirt and her dress, i made separate selections of those areas and treated each with my 32 band gray plugin. this allows you to adjust the grays up and down in bands. very handy for images like this. rather than try to clone out the smudges and dirty look, i simply selected those areas and adjusted the tones i wanted to change, blending them into the other tones that were there."

Unfortunately, it looks like it's been over a year since he's been active so I can't just ask him. Hoping someone else goes "oh yeah, THAT!"

Although on re-reading it, this is quite a few versions of Photoshop ago - I wonder if the same effect could be achieved now through a selective color selection on a layer set to luminosity? Or through curves, but I'm really bad at using curves for small-scale corrections instead of global adjustments. I was hoping to find an alternative.

[Cameraken]

Re: 32 band grey?

Hi Julie

I remember that thread.

Kraellin was using a 32 band filter that was made with Filtermeister. The initial thread got segmented but some of it is here

http://www.retouchpro.com/forums/software/13502-filtermeister-gray-map-filter.html

the code in that thread will run by installing the Filtermeister plugin available here

http://www.filtermeister.com/

Hope this helps

Ken

[skoobey]

Re: 32 band grey?

One of the ways to make 32 bands of grey is to use posterize at 32 levels, then desaturate it.

[Aladdin]

Re: 32 band grey?

Julie, What are you trying to achieve anyway? As you might be aware, there are many ways to do the same "thing" in photoshop. Someone here might know.

@andrewrodney: Thanks, but no, thank you, I do not want to go there...been there, done that, nowadays, I only care about results, I will leave the How To to the younger generation