Comments on: Episode 032: Fade to Gray – Monochrome conversion (1)

By: Rolf

Rolf — Sun, 19 Jul 2009 00:09:09 +0000

As you may have noticed this is a project about digital image manipulation. We do it with the light on here.

Why not use the technology that is available? And why do you use such modern stuff like industrial plastic film instead of making your own emulsion on glass plates? That is the real stuff! (I did that once – was fun but not to be repeated.)

By: Sergio

Sergio — Sat, 18 Jul 2009 23:26:54 +0000

Another way to achieve the BW look is to shot the REAL THING! Whata concept. Why settle for imitation BW?

By: ansel-adams-fan

ansel-adams-fan — Fri, 18 Jul 2008 12:45:43 +0000

Great to find that collection of Ansel Adams photographs which you can use on your web site! I’m a fan of this guy and will be happy to feature some examples of his work on my site, /Link removed by Rolf – commercial site for selling posters./

By: Raymond

Raymond — Thu, 27 Mar 2008 21:35:03 +0000

Very good!

By: Meet the GIMP « Ang Pilipino GIMP

Meet the GIMP « Ang Pilipino GIMP — Sat, 08 Mar 2008 23:26:48 +0000

[...] Episode 032: Fade to Gray – Monochrome conversion (1) [...]

By: Rolf

Rolf — Sun, 17 Feb 2008 14:47:15 +0000

Yes, there are countless ways to come to the same result. An other way is to grab the green channel (least noise) and try to work from there. But channel mixing is even better. See next episode…

By: Rootie

Rootie — Sat, 16 Feb 2008 23:15:22 +0000

now i also found out that the lightness method would be the lightness layer when converting/decomposing the image to HSL

By: Rootie

Rootie — Fri, 15 Feb 2008 23:10:45 +0000

these are the formulas how the grey value is calculated with the various desaturate methods (from the gimp doc)
Average Brightness = (R + G + B) / 3
Luminosity = 0.21 * R + 0.71 * G + 0.07 * B
Lightness = Ã‚Â½ * (max(R,G,B) + min(R,G,B))

the average method is the simplest method to create a greyscale image… it just treats each color channel equal. this is more a technical way

the luminosity is adapted to the human eye. it reflects the sensitivity of the eye to the different colors

well i don’t know where the lightness method comes from

near the end of the video you showed those small differences in the rgb values (i tried to reproduce this… but somehow i could not find pixels with different rgb values).
but i do not think that these are rounding errors.
this can be a method to virtually increase the number of grey values
it also uses the fact that the sensitivity of red green and blue of the eye is different
for example
0,0,0 <- base color
0,1,0 <- this is a little brighter for the human eye
1,1,1 <- this would be next real grey value
the color fault is so small that it is not visible
if you e.g. draw a gradient from one color to another then this method is also used

By: Serge Gielkens

Serge Gielkens — Wed, 13 Feb 2008 16:52:01 +0000

Rolf,

Thanks for the link to TftTF. That was elucidating.

It sounds simple, now I have to experiment with it in real life.

By: Ger

Ger — Wed, 13 Feb 2008 06:02:52 +0000

I like to mention something remarkable.
Have you ever tried to convert a chroom object into monochrome? I have.
And only the background turned into monchrome. The chroom object already was monochrome. Isn’t that remarkable? I never thought about it.

By: Rolf

Rolf — Tue, 12 Feb 2008 22:16:08 +0000

No, zone mapping has to start with the exposure – and I shot this with my point&shoot by simply pointing and shooting.

The Zone System is in part translatable to the digital world – Chris Marquardt has done something about that at Tips from the Top Floor..

By: Serge Gielkens

Serge Gielkens — Tue, 12 Feb 2008 21:17:23 +0000

This is going to be an interesting series. Now that you mentioned Ansel Adams here, I begin to wonder if you figured out some kind of zone mapping for the picture of the leaf at 23HQ.com.

Very nice show, Serge