Canyon Conumdrum

[ggroess]

Mike has asked me to shoot the image from a canyon that cannot be improved in LAB. 
I know you all love a good challenge. 
My best result is in RGB so far....
This image was shot at sunset it is a lengthy exposure....

Give it a shot...

Greg

[mikemeister_admin]

I think you need a course in exposures!! - only joking Greg.

This is not the day to post a challenge and say Lab is impossible.

Just a quick fiddle only in Lab - I'll try later in the week when I have time as this is persumably not the effect you are looking for!

Chris

[ianbowie]

Greg,

My shot at it in Lab only.

Ian

[ggroess]

The rock in the foreground is too blue.....Try it in RGB and set a reasonable neutral and you will see what I mean...

Mike's challenge to me was..."go on vacation and try to shoot an image of a canyon that cannot be improved in LAB."

90+ percent of the images I shot last week can indeed be improved in LAB...I found this one to be a real problem child...I will post my RGB later this week....

Greg

[ianbowie]

Greg,

I see what you mean ..... second try.....

[derekfountain]

The rock in the foreground is too blue.....Try it in RGB and set a reasonable neutral and you will see what I mean...

Mike's challenge to me was..."go on vacation and try to shoot an image of a canyon that cannot be improved in LAB."

90+ percent of the images I shot last week can indeed be improved in LAB...I found this one to be a real problem child...I will post my RGB later this week....

Greg

What are the characteristics of an image that make it unsuitable for correction in Lab mode?

[ggroess]

Well for me it has been the fact that no matter what I do to it I cannot make it look like it should.  I cannot get rid of the yellow green cast when I set a single neutral. 

It can be improved but When I use RGB I get much... much better results.

Greg

[derekfountain]

Well for me it has been the fact that no matter what I do to it I cannot make it look like it should.  I cannot get rid of the yellow green cast when I set a single neutral. 

Here's my fix. I also couldn't get anything decent looking from lab mode. Looking closely at the image with the aid of the hue clock, you can see there's a blue cast which gets deeper as the tones get darker. I think that's the key; the CM help text says that RGB is good at fixing problems where a colour cast is associated with a change in brightness, and that's exactly what we have here. I can't claim to understand the theory why that's true, but the curve shown below does get a decent result.

After the colour fix with RGB mode, I added another conventional pass in Lab mode to lift the brightness and increase the saturation. It's actually possible to lift the brightness to the point where it looks like a daylight shot, but since it was a long exposure sunset shot I tried to keep it a bit dark and saturated, like perhaps the view appeared at the time.

[ggroess]

Derek,
That is where I got it in RGB as well...I like this one so far....

Greg

[mikemeister_admin]

I think that is absolutely excellent Derek,

I'm puzzled by one thing - I tried to copy your curves to see what was going on, and I noticed that I could not get the histograms to be anything like yours (see below), especially the red and green channels - so I guess you did at least 3 passes.  The first to lighten, then RGB, then Lab - is that right?

I had this problem on the course where I could not get my histograms to look like other people's - Mike suggested the difference between precise mode being on/off.

Does anybody else have this problem with histogram representation?

Thanks
Chris