Tone-mapping on the way from Color to Monochrome.

[Deleted member 82967]

Tone-mapping on the way from Color to Monochrome.

There are many, many ways to convert color to mono. There are also several fancy ways to map tones from one color rendition to another. However, I find that going straight from color to mono with a simple luminance RGB-to-Y' can result in quite a bland image for my taste.

A while ago, I got the GIMP and discovered fancy tone-mapping in various forms - one of which (Mantiuk 2006) jazzes up a bland color image considerably - enough to where a simple luminance RGB-to-Y'is more than adequate.

A sequence applied to a DP2 Merrill low-res street image:



Each step above is at option default settings. Hopefully it is obvious which is which! Bottom Right is Bottom Left with a bit of USM applied.

Not saying this method is best; it is only posted for interest.

What's your method?

 

[Deleted member 82967]

There are many, many ways to convert color to mono.

For an introduction to and an exhaustive test of various types of color image and various methods see:

Martin Cadik - Perceptual Evaluation of Color-to-Grayscale Image Conversions Overview

Martin Cadik - Perceptual Evaluation of Color-to-Grayscale Image Conversions

From which it would appear that using only one method does not suit all possible images. So, hopefully, your editor has various options in that regard ...

 

[Deleted member 82967]

For an introduction to various types of color image and various methods see:

Martin Cadik - Perceptual Evaluation of Color-to-Grayscale Image Conversions Overview

From which it would appear that using only one method does not suit all possible images. So, hopefully, your editor has various options in that regard ...

Here's the gospel according to Pat David - a well-known Gimpster:

GIMP - Digital B&W Conversion

Spot the Spinal Tap reference ....

 

[Deleted member 82967]

Here's the gospel according to Pat David - a well-known Gimpster:

GIMP - Digital B&W Conversion

Spot the Spinal Tap reference ....

Check this out - split-toning gone mad:

http://theabyssgazes.blogspot.com/2010/03/teal-and-orange-hollywood-please-stop.html

 

[Deleted member 82967]

What's your method?

Too technical for this forum?

 

[Arnold Layne]

Too technical for this forum?

For sure it is for me. I just use the B&W option at C1 and then a bit here and a bit there.
Anyway thank you, I find it very interesting, an the "Teal and Orange - Hollywood, Please Stop the Madness" made me laugh.

 

[Deleted member 82967]

Another technical pre- conversion method (Wavelets) ...

The victim - embedded JPEG from a raw file, un-adjusted ... pretty bland, eh?:



Some Wavelet processing which allows adjustment by detail size; large selected for cloud contrast:



Then 'color to gray' in the GIMP, messing with the parameters, a bit over-the-top:

 

[Deleted member 82967]

And now for Contrast-Limited Adaptive Histogram Equalization (CLAHE):

Contrast Limited Adaptive Histogram Equalization

End result after C2G:



Read here for what CLAHE does, it's too much to summarize:

Adaptive histogram equalization - Wikipedia

en.wikipedia.org

 

[rfaspen]

Neat results from that CLAHE application.
I tend to use SilverFX-Pro and only occasionally stray far from their offering of algorithms. I can map tones if desired and I have done so quite infrequently...seems like just one of those case-specific tasks. No?

 

[Deleted member 82967]

Neat results from that CLAHE application.
I tend to use SilverFX-Pro and only occasionally stray far from their offering of algorithms. I can map tones if desired and I have done so quite infrequently...seems like just one of those case-specific tasks. No?

Agreed. Different scenes ofren benefit from different parameter values or even processing methods.