OK--Finally am jumping in with Duck image... :-)

[mikemeister_admin]

Hi all,

I finally got my screen calibrated and started in on the Duck image.  In going through the Wizard and setting the dark, light and neutral, I tried two places for the neutral:  the gray band on his leg and a portion of the rock behind him that look particularly neutral.  It may be my monitor, but I felt that the gray band had some green cast to it, so I chose the rock.  Here are the two different neutral choices and then the final image.  I had a little trouble figuring out the Brightness part of the Wizard.  I started out moving the top slider while in LAB and the photo went berserk.  After playing around I realized that the top slider was for RGB and the bottom one (LAB only--DUH) was for LAB.  My question--if you change the upper slider while in RGB mode, does those effects get added to the mix when you switch to LAB, or is it literally one OR the other?  If the latter, if you chose RGB at this point, how does that effect all the other work you've done in Curvemeister?  I did use the LAB mode for the brightness option, but I see that the image is back to RGB when I clicked finish.

Final thoughts:  I think the duck looks good--I might brighten up his eye, but I think the background is too saturated and busy--which has nothing to do with this assignment.  As a final-FINAL image I'd burn the background, or apply more blur and desaturate it a bit.

Curious as to how well my monitor calibration worked.  Does everyone else look at a calibrated monitor?

Rhonda

[sjordan93436]

I use a calibrated monitor.  There is a deep hole you can go down and should go down if your profession requires it.  Color of the ambient, quality of the monitor, etc.

Correct me.  If you correct in RGB, I think you need to exit and redo or reset your curves to change to LAB.  I think.  One of the advantages to CM is being in RGB and curving in LAB or HSB without changing color.

If you set neutral with a point, you almost always should shop or move it around.  I found some trouble with the wizard and brightening the picture.  Setting shadow or highlight requires the "shopping around" mode. 

These points are backward.  I chose the rock, also.    There maybe someplace on the band that works. 

[ggroess]

Rhonda,
Overall I think you have a green cast in the shadows and a blue cast in the highlights...See my screen shot. 
This is a touchy neutral...Please check your sample size 3X3 might make it hard to find a good neutral.  You might want to go to 5X5.  If that doesn't work try 4X4. 
The Band is usually a safe bet.  It is aluminum and has been used for quite a while to set this neutral.

But you bring up an excellent point both of you.  If you are going to adjust images visually...Something I do often......you need to know your monitor is reasonably calibrated.  I check mine about every two weeks with a I-one2 I have found that the monitor drifts a bit but usually I am pretty close.  It takes 10 minutes to do and saves a lot of headaches later.

Greg

[mikemeister_admin]

Thanks sjordan and Greg for your comments.  IGreg, i have no idea how colors work with the numbers, other than every color has a RGB profile of numbers.  Is the image/numbers you posted below mine based on my image or one you have done?  Does the manual have guidance on this, and on how to change the size of the eyedropper for selecting the various thresholds?  Unfortunately I know that "numbers theory" is a deep subject and one that cannot be grasped in 15 minutes.  At this point, I am using the Wizard, but don't really know how the LAB color space works by looking at the various histograms.  I can see how they effect the image, but they mean nothing to me as far as understanding why.  Therefore, without the Wizard I can't look at an image and figure out what I might do with the various channels to obtain a desired result--other than just play around.  In RGB, I understand that the scale is linear from 0 - 255, but it does not translate to LAB and the various channels.

"Correct me.  If you correct in RGB, I think you need to exit and redo or reset your curves to change to LAB.  I think.  One of the advantages to CM is being in RGB and curving in LAB or HSB without changing color."   OK, I'm a beginner.  I know you can chose LAB mode in Photoshop without being in Curvemeister.  I thought that one of the advantages of Curvemeister was that it created a little LAB workspace for you to work in.  I was just surprised that when I saved the changes, it went back to RGB--or so I thought.  Is this correct?

[ggroess]

Rhonda,
If you have done this with the wizard I commend you...that is a very good correction using the wizard.  Numbers can be a deep subject but i think people put too much into it.  I try to keep it simple and I am sorry for the confusion...( Waves @ Art )...

The Idea behind numbers is that you can find known points in the color scale by looking at the numbers.  Think of it as mixing paint.  When you go to the hardware store and order paint they have a recipe for the "hue" that you want to buy.  They mix it "By The Numbers".  In CM we use the hue clock and numbers to help us find our way back to a known value like gray. 

In RGB the leg band on the duck should at some point be neutral.  By the numbers we express that as (XX,XX,XX) where the xx's are replaced by a number.  It can be any number between 0 and 255.  0 is total black and 255 is total white.  In your duck the sampled point reads  144,147,179...wow...what does that tell me....

The numbers are R G B so the R value is 144 the G value is 147 and the B value is 179.  They need to be equal to be neutral.  the closest neutral to your current setting would be 145.  so making each value 145 by adjusting the curves makes that sample point neutral and by extension adjusts the rest of the image. 

If you have picked a "wrong" sample point and you make it the neutral the rest of the image looks all messed up.  You would then need to find another neutral...you see this in the wizard when you move the neutral point around.  When you set a neutral you are telling CM to make the RGB values (numbers) all the same under the sample point. 

In most cases until we get to the "By the Numbers" corrections the hue clocks are sign posts on the road and they just give us direction.  We can choose to ignore them but just like road signs; you ignore them at your own peril.

Lab is a totally different color space and it has it's own rules and numbers.  That is why it is so confusing at first.  The grids do not make sense and the numbers are all messed up...

In LAB the color is separate from lightness. (L channel)  This allows you to adjust the contrast and lighting without touching the color...Very powerful....The A and B channels contain all the colors in the image.  The trick is that the exact center of the channel grids is neutral.  We express that as 0,0 for lab.  So when you set a neutral in LAB you are telling CM to make the point selected to be (X,0,0)  Where X can be any brightness value from 0 to 100.  Every Color in RGB has a matching LAB color but Lab actually has more color in it that RGB cannot see.  There are LAB values tha tRGB cannot create..they are considered "out of gamut"  and we need to be aware of them but not afraid of them.  They are usually very strong colors that would ever be printed.  There are exceptions and actual mileage may vary....

I'm hopeful that by looking at the numbers in the duck and reading the explanation above they will start to make sense...If not please keep asking...it is one of the things you came here to learn.
Greg

[mikemeister_admin]

Whew--that was a great reply, Greg.  I sort of get it.  OK, if the exact center of the grid in LAB is neutral, is that not the same in RGB?  In an RGB curve if I want to effect the midtones, I place a spot on the middle and go from there.  In an RGB curve I can work on each color separately or combined.  I usually work combined.  Is the purpose of the RGB curve to affect the brightness and contrast of each of those channels, whereas in LAB, only the L channel affects the brightness and contrast, and the A & B channels affect the colors.  (I'm trying to translate what you said into my words to see if I get it.) 

So how could you tell that I had a green contrast from the numbers?  In my sample of the wing the numbers are:
R 209/217
G 227/230
B 255/243

So:
What are the two numbers separated by the slash?  Why wouldn't neutral be
L X/X
A 0/0
B 0/0

If the color didn't have a cast, would they all be the same number?  i.e.:

R 209/209
G 209/209
B 209/209

Thanks again.  Man!  I need to move on to the next image.  I think the threshold mask is why the wizard worked for me.  That thing is a winner!  I know they have this in Photoshop but I've not learned when and how to use it.

Thanks so much!
Rhonda

[mikemeister_admin]

Sorry--I am looking for the download place for the original images of the carousel and the people with the kites.  Have clicked everywhere I think that they may be posted, but it eludes me.  Should I just cut and paste the image in the tutorial?

Thanks.

Rhonda

[mikemeister_admin]

http://www.curvemeister.com/forum/index.php/topic,3140.0.html

Scroll down to the link to the classroom page and click on it.  On the page that you comes up, go to the bottom and under "Week One", click on the WWW link.

[mikemeister_admin]

Sorry to deluge you--Thank you for posting the hue/clock video.  It goes by pretty fast for me, but if I stop it and replay each 30 seconds or so for a number of times, I almost get it.  So no need to answer my questions about the double numbers (R 209/243).  May have more questions once I've digested the video--tomorrow!  Have a camera club meeting tonight.

[ggroess]

Whew--that was a great reply, Greg.  I sort of get it.  OK, if the exact center of the grid in LAB is neutral, is that not the same in RGB?

They are different color spaces.  The actual geometry behind them is different   just understand this point for now.  In LAB you have 2 color channels and 1 lightness channel.  The A channel is Red/Green and the B channel is Yellow/Blue.  In the center of the grid is neutral. " 0"

To describe a color in LAB you have 1 value from each (L=XX,) (A=(+/-) X),( B=(+/-) X)  We write it as L(x), a(x),b(x)  or ...L10, 20,-20.  That value describes 1 point in Lab color space.  If the value is (L10, 0,0) then it would be neutral otherwise it has some color value so a (L10, 1,0) would have a red cast since the A channel is a positive number. 

  In an RGB curve if I want to effect the mid-tones, I place a spot on the middle and go from there.  In an RGB curve I can work on each color separately or combined.  I usually work combined.  Is the purpose of the RGB curve to affect the brightness and contrast of each of those channels, whereas in LAB, only the L channel affects the brightness and contrast, and the A & B channels affect the colors.  (I'm trying to translate what you said into my words to see if I get it.) 

Yes you have it.  In RGB you work on each channel and you changes are spread across the brightness.  The mid tones are in the middle of each color channel.  In LAB the mid tones are in the middle of the L channel regardless of the color.

So how could you tell that I had a green contrast from the numbers?  In my sample of the wing the numbers are:
R 209/217
G 227/230
B 255/243

If we look at the Red numbers alone R= 209 is the original value for the pixel the 217 is the new value after the curve is applied.
So for your sample point the color is actually a blue/cyan the red and green channels are lower than the blue. If you wanted it to be pure white for instance you would raise the red and the green to 255 to match the blue  OR lower the blue to match the green and red values but then it would be gray since you are dropping away from 255.  Which way to go??  Look at other ares and see if the blue is a problem there as well.  If it is you might want to effect the blue and see if the rest of the image improves first.

So:
What are the two numbers separated by the slash?  Why wouldn't neutral be
L X/X
A 0/0
B 0/0

Again the second numbers are the values after adjustment.  L(x), 0, 0  is the neutral.

If the color didn't have a cast, would they all be the same number?  i.e.:

R 209/209
G 209/209
B 209/209

Those numbers would occur if your hue clock was set to a pure neutral to begin with and you made no change.

Thanks again.  Man!  I need to move on to the next image.  I think the threshold mask is why the wizard worked for me.  That thing is a winner!  I know they have this in Photoshop but I've not learned when and how to use it.

We use it all the time in CM and we need to turn off the wizard now....LOL Cause once the training wheels come off this lil' baby can really do some cool stuff...

Thanks so much!
Rhonda

You are quite welcome...it was a great question and answer exchange.
Greg