Color walks into a bar...

[Abitconfused]

Young Mr. Erstwhile Tone walks into the Midtone Bar and the bartender, a Gray from Roswell, New Mexico says, "This is the Midtone Bar you have to be older than shadows to be here, show me some ID." What RGB information has to be on the ID so that the bartender will know Mr. Tone is old enough to be a Midtone?

[Mike Buckley]

I consider the mid tones to be the middle area of a traditional S-curve of the tone curve, the area that is mostly a straight diagonal on the graph. The S-curve is used partly to boost mid-tone contrast and that area of the curve depicts those mid tones to which contrast is increased. That area is roughly the luminosity values of 100 - 150. It's no coincidence that if you divide the luminosity range of 0 - 255 into thirds, the middle third is roughly the values of 100 - 150.

[xpatUSA]

Young Mr. Erstwhile Tone walks into the Midtone Bar and the bartender, a Gray from Roswell, New Mexico says, "This is the Midtone Bar you have to be older than shadows to be here, show me some ID." What RGB information has to be on the ID so that the bartender will know Mr. Tone is old enough to be a Midtone?

I love it!

Taking "Gray" to mean luminance or luminosity, approx R*0.3+G*0.6+B*0.1 must total 118 or more, assuming 8 bits per channel.

[DanK]

I'd take a different approach from Mike's. I'd say that "midtones" are whatever part of the middle of the distribution you want them to be. The application of an S-curve is a good example.

Applying that adjustment spreads out the midtones and compresses the ends of the distribution. For example, what had been the range of 0-60 might end up squashed into 0-40. The middle range is expanded accordingly. I'll post an original histgram with an S-curve overlayed on it, and the resulting adjusted histogram, which shows this effect:





In contrast to this, you might make the concave areas much smaller in another image, depending on the effect you wanted. It wouldn't matter: in both cases you are expanding the midtones and compressing the extremes. If you assign arbitrary cuts, this just becomes harder to describe.

[Mike Buckley]

Applying that adjustment [an S-curve] spreads out the midtones and compresses the ends of the distribution.

I had never thought of it that way but that is exactly what happens. Thanks for the enlightening info!

[xpatUSA]

I'd take a different approach from Mike's. I'd say that "midtones" are whatever part of the middle of the distribution you want them to be. The application of an S-curve is a good example.

In which case, what is the lower limit of these mid-tones that would allow Mr Erstwhile into the bar?

I was wrong because my 118, or 127 if you must, is presumably in the "middle" of these mid-tones.

[Mike Buckley]

my 118, or 127 if you must, is presumably in the "middle" of these mid-tones.

Yes, but lower limits are part of the bias intended to increase the size of the bar's target market and, thus, also increase its sales.

[xpatUSA]

Yes, but lower limits are part of the bias intended to increase the size of the bar's target market and, thus, also increase its sales.

Indeed, Mike, you already answered my question with that "100 to 150" (I missed that, no idea why - probably in too much of a rush!) . . .

[tao2]

Master Erstwhile does not require a colourful ID..Mr Tone need only be, "in the Zone"...,