A Curvemeister Look at Color By The Numbers

[ggroess]

Art,
In shot 2 the S/H/N have not changed...ok..the Neutral slightly...
Our goal is to get the best image..sometimes the numbers are less than perfect. I have been known to cheat.... Remember the sample size has a lot to do with this...

Greg

[mikemeister_admin]

Is there any way to set the sample size to stay at 3x3 instead of constantly having to change it from 5x5 to 3x3?  Every time you open CM, the sample size is at 5x5, and it gets annoying to have to keep changing it to 3x3.

[ggroess]

Are you setting it using the Config wrench?  It should stick from there...

Greg

[mikemeister_admin]

No, I didn't realize that was how to set it.  I kept clicking on the wrong thing.  I noticed that you have the shadow target set at 5, 5, 5 and the highlight target set at 250, 250, 250.  Any special reason for that, as opposed to 0, 0, 0 and 255, 255, 255?

[ggroess]

For me this keeps the highlights and shadows from being clipped if I drop below these levels. 
I use it for printing locally and in general to preserve the extreme details.

Many people use these settings at even higher levels..you might want to play around with them when you print something.  They can save you sometimes...If the highlight and shadow in your image are not outside of these settings you do not need them. 

Greg

[mikemeister_admin]

1.  What is the difference in effect between setting a neutral and averaging all the RGB neurtal-ish colors and manually moving RGB to the averaged number? 

2.  It seems that you can move a set neutral in RGB, but not in LAB.  Why?  You can also only set one neutral in LAB; if you set more than one, it marks the spot with a "n", but it has a red x through it. 

3.  I naively assumed than when you set a neutral point that you forced all channels in RGB to be equal numbers, i.e. 125/125/125 or 140/140/140.  This is not the case.  If setting a neutral doesn't reset the colors to neutral, what does it do?!

4.  A quote from you:  "As for the average.  Time and testing has shown that for the mid-tone neutral   you really should average the new values because you have corrected the image some what and the changes reflect the tonal range and contrast as the image is after you set the highlight and shadows. The Idea is to hold the same tonal range as the original  not necessarily move the tonal range with the correction since you are working on all channels."
Huh?  I was with you until the last sentence.

OK, enough bugging you for now!

[ggroess]

1.  What is the difference in effect between setting a neutral and averaging all the RGB neurtal-ish colors and manually moving RGB to the averaged number? 

Sometimes very little...but often times you may not set all the values to be exactly equal...Remember it is all about the sample point and equal numbers creates gray...If it is a known gray you are in perfect shape...if it has a slight tint to it it can cause problems...the drummers image is a great example of not completely knowing the real value of the gray.

2.  It seems that you can move a set neutral in RGB, but not in LAB.  Why?  You can also only set one neutral in LAB; if you set more than one, it marks the spot with a "n", but it has a red x through it. 

You can set the "point" in LAB but CM knows that lab can only have 1 neutral.  It turns off the neutral pin if you set another...you can toggle between them by clicking on 1 or the other...

You just set off something in my head...I'm going to try something and see if I can trick CM and LAB...

3.  I naively assumed than when you set a neutral point that you forced all channels in RGB to be equal numbers, i.e. 125/125/125 or 140/140/140.  This is not the case.  If setting a neutral doesn't reset the colors to neutral, what does it do?! 

Let me try it and see what I'm seeing there might be a fly in the ointment....

4.  A quote from you:  "As for the average.  Time and testing has shown that for the mid-tone neutral   you really should average the new values because you have corrected the image some what and the changes reflect the tonal range and contrast as the image is after you set the highlight and shadows. The Idea is to hold the same tonal range as the original  not necessarily move the tonal range with the correction since you are working on all channels."
Huh?  I was with you until the last sentence.

OK...lets say I set a hue clock on a gray and it's values are R105, G210, B115.  If I adjust them to be neutral at 210 have I not changed the brightness of that point up to 210??  The idea is to move the mid tone last so that you have set the upper and lower limits on the image and then set the mid tone neutral.  That way you will have less to do in the middle. 

I have found that by waiting until I have the thresholds set and then calculating the new average from the "New" numbers created when I adjust the ends...I get a better tonal range for the mid tones..Less overall change...

Greg

OK, enough bugging you for now!

Not a bother at all...
Greg

[imported_julie]

Hi Greg,

Hope you are well.
I hope its still ok use this.
i  have been giving myself a refresher on BTN. What happens when you do not have a neutral in the photo. I have nothing grey in lots of photos and am wondering what i can do. Or have I completely misunderstood and is it a mid tone in brightness?
I think i need to set up some private lessons

Julie

[ggroess]

Julie,
when there is no grey you can still set a highlight and shadow value and make them neutral as needed.  After that eliminate any impossible colors like green hair or magenta clouds in a bright blue sky.

BTN is more about real color than having a S/H/N in every image.

Greg

[mikemeister_admin]

Hello!  Good to see this thread is still alive!

So I'm up to my usual--questions about what is probably obvious:  BTN? (Black, ?, Neutral?)

Thanks!

Hi Julie!

Rhonda