Working with ICC Profiles

There have been some posts recently regarding proper use of ICC profiles, and specifically how to use AboutDigicam.com's TrueColor series of profiles.

(I don't have any affiliation with AboutDigicam.com, other than I think they did some good work.)

Some have complained about low contrast in some linear conversions. I think I've found a solution that I'd like to share with you.



"Before" is a RAW conversion straight from the camera, no sharpening, levels or adjustments of any kind. "After" is, well... after!

I'll re-post the precise workflow I use to do this. It takes about 1 minute, and should work on any image, from any profile, 8 or 16bpp.

For those not interested in the details, you can download a couple of free actions I made for you to do this (they're only 1 step each!) from:
http://www.gibsononline.net/misc/retouching/Brad 's%20Restore%20Contrast.atn

"Restore Contrast" is the workflow outlined below, without the gamma boost step (step 6 below), while "Restore Contrast II" includes step 6 below. (wojtek and marius, if you want, you're welcome to include the actions in your TrueColor packages. I can only imagine it will reduce your support workload!!)

The Workflow:
--------------------

Ok, so how do you do this? Here's the workflow, reposted from another thread. Don't worry about the '1D' or 'color matrix' stuff if you don't have a 1D-- this should apply to any camera, any profile. Here it is, step-by-step:

1) Shoot image in Raw, Matrix 4

2) Perform linear 16-bit TIFF conversion in BreezeBrowser (or your conversion tool of choice), assigning EOS-1D Linear Profile (or your profile of choice)
3) Open in PS7 and convert to working space (AdobeRGB)

At this point I have what appears to be a low-contrast version of the image. So then I:

4) Mode-> Adjustment-> Curves...
5) Options...-> Enhance Monochromatic Contrast

Contrast should be good now and (this is important) color balance has been preserved . If image is still a bit dark, you can optionally provide a slight gamma boost:

6) (Optional) Map input level 63 to output level 70 or so.

I like this work flow because:

• it gives good results
• doesn't require custom S-curves
• allows me to increase the contrast and control the amount of clipping I want (even no clipping at all)
• preserves the color relationships so I don't induce any casts. Isn't that why we bought the profile in the first place?

Additionally, it:

• maximizes contrast of any image regardless of content
• works on 8 or 16bpp images
• can be used on any profile, even Canon's, or none at all

I hope that's useful! Enjoy!
Brad

Hi Bradley,

Many thanks for your action, I have just tried it on a few images and it seems to go a bit harsh on the contrast side, I have found just using levels adjustment gets the contrast ok.

I am still learning all the time about PS, maybe I am missing something, here is my results,

Regards Sean,



http://www.seanpalmer.hostinguk.com/D30/

I am not sure how or whatfor the profile you used was created, but a color profile is customised and you really need one for your own device. Otherwise the apparent representation of the image might be more pleasing or saturated but that's it...

You also need a profile for the specific raw-conversion settings you use, that is perhaps what the matrix 4 is (?). This means one for low saturation, sharpening and contrast, another for some other combination,...
and perhaps even one for every lens, to be exact...
That might partly explain the lack of contrast you experienced.

furthermore the low contrast might be due to the fact the profilling makes for more distinct tonal differences in your image which makes it look less contrasty however it is not (euhm ... ;-). Each high-grade camera tries to preserve detail instead of turning out a very vivid and peprocessed photograph. That is also a reason to make full use of the 10-14 bit depth, as you need to remap the tonal range yourself which is generally bound to make it more limited.

Each adsjustment made afterwards (levels, curves or whatever leads to a color shift...

But accurate color is not the goal of most photographers... the main thing is the image must look good.

Are things being thrown at my head now, "as we speak", LOL ...

BTW: if you look at the raw-converted images in this page of mine you might also find them lacking contrast. The top-most image is fixed using curves.
http://users.skynet.be/bk244311/fora/lintest/CRW-comp.htm

However the standard canon-conversion might look more vivid etc, the color is less correct. blue roof-tiles, white wall etc...
Why couldn't they write their software based on my camera ?

Hi, Sean,

You're absolutely right, Sean, the action is a bit 'harsh' but that's because it's pretty much maximizing the contrast.

Try editing the action and changing the clip values from 0.5% to 0.1 or even 0, you'll see that it's softer then. If you find a value you like, chances are it will be good for a wide range of your images; you'll be able to streamline your workflow.

Another option is to try Edit-> Fade right after most any operation to 'back off' some of the effect. (I often do that after a nik Sharpener operation.)

Technical stuff:
--------------------

After thinking about it, I realized that doing this in Levels and doing it in Curves is actually doing the same thing! (And sure enough there's even an Options...-> Enhance Monochromatic Contrast button in the Levels dialog, too!)

Expanding the levels in Levels is the same as increasing the the slope of the line in Curves.

Moving the levels midtone slider is the same as choosing what input level maps to output 127 in curves (although Levels seems to use a 'flatter' curve than does Curves.)

I guess the bottom line is this will work equally well either way!
Brad

To be honest, I'm not sure I followed everything in your post, but I can answer your first question.

1. 1 I'm looking for a profile to give me colors as close to the original scene as possible.
2. 2 I'd like to use linear conversions to as to preserve as much shadow and highlight detail as possible.

For reasons I'm not 100% clear on (I'm sure the AboutDigicam guys can tell you much better than I could), the TrueColor profile seems to have accurate color but a low dynamic range.

So my quest was to find a way to be able to 'batch correct' my images without introducing a color cast.

I hope I've answered your question...
Brad

bradley phillip said:

Some have complained about low contrast in some linear conversions.

Click to expand...

From the little bit of fiddling and comparing I've done with linear profiles it's apparant that both profiles I used (aboutdigicam's basic profile, and FM's profile, both with and without his action) steepen the curve at both ends thereby increasing detail in shadows and highlights, but at the expense of decreased contrast (flattened curve) in the mid-tones. The trade-off is inevitable, but arguably preserves more data for further manipulation, keeping your options open as to what's important in the image.

The same effect can be achieved with a non-linear conversion with custom curves, or without but followed by a curves adjustment in PS. When working in 16 bits for final 8 bit output I'm not sure there's any detriment to doing it this way versus linear.

I find that the linear profiles work well with some images and not so well with others, wrt being close to my final goal. But it's really pretty simple to adjust contrast in PS with a curves adjustment - and is something I almost always do anyway if I'm fussy enough about an image to be using linear conversion.

In any case, the difference in colors between linear/profile conversion vs non-linear seems more significant to me because color balance fiddling is something I prefer to avoid in PS.

• DL

bradley phillip said:

1. 2 I'd like to use linear conversions to as to preserve as much

shadow and highlight detail as possible.

Click to expand...

But the reason linear conversion preserve shadow and highlight detail is because they give up some mid-tone contrast. You can't have your cake and eat it too. But the thing is, as I'm sure you're aware, is that you can then decide in PS what the trade-offs are for a particular image and adjust it accordingly.

AFA color accuracy, imho the standard canon non-linear conversion gives more accurate colors although I sometimes prefer the linear color result artistically. But I haven't tried the true-color profiles. Maybe I will. Do you have any comparision shots processed both ways?

• DL

Brad et all,

In your workflow you mention:

Member said:

4) Mode-> Adjustment-> Curves...
5) Options...-> Enhance Monochromatic Contrast

Click to expand...

I haven't upgraded (yet) to PS 7, have you any idea of what actions I should take in PS6.01 to achieve the "Enhance Monochromatic Contrast" step?

BTW: I bought the AboutDigicam TrueColor set of profiles and I'm so far VERY happy with them!

I have tested a number of other linear profiles (see
http://www.dpreview.com/forums/read.asp?forum=1019&message=3329813 )

but the AboutDigicam profiles seems the most accurate and gives me much less color problems.. but now I have to find a way to increase the contrast in an intelligent way...

Any advice on raising the contrast (beside the ordinary curves, levels or brightness/contrast methods) is highly appreciated. The "Enhance Monochromatic Contrast" seems interesting..

Thanks for your valued help and patience!

:O)) Bo W

You're welcome Bo.

Hmm.. Unfortunately, I uninstalled 6 shortly afte I put 7 in...

I didn't think this was a new feature-- the Photoshop help says this "Enhanced Monochromatic Contrast" is the algorithm used by the Auto Contrast function, which existed in PS 6 (if I remember correctly).

Open up the curves, or the levels window. The last button on the right should say "Options.." It's in there...

Let me know if it's really not there. Maybe I can come up with a workaround.

Brad

Bo W said:

In your workflow you mention:

BWan said:

4) Mode-> Adjustment-> Curves...
5) Options...-> Enhance Monochromatic Contrast

Click to expand...

I haven't upgraded (yet) to PS 7, have you any idea of what actions
I should take in PS6.01 to achieve the "Enhance Monochromatic
Contrast" step?

BTW: I bought the AboutDigicam TrueColor set of profiles and I'm so
far VERY happy with them!

I have tested a number of other linear profiles (see
http://www.dpreview.com/forums/read.asp?forum=1019&message=3329813 )

but the AboutDigicam profiles seems the most accurate and gives me
much less color problems.. but now I have to find a way to increase
the contrast in an intelligent way...

Any advice on raising the contrast (beside the ordinary curves,
levels or brightness/contrast methods) is highly appreciated. The
"Enhance Monochromatic Contrast" seems interesting..

Thanks for your valued help and patience!

:O)) Bo W

Click to expand...

Brad,

It seems as I have to upgrade to PS7...

The (only) Options button in the PS6 Curves dialog applies to the Auto function and is visible when you press the Alt key. I forgot...

Unfortunately the only options available here is to set white and black points.

BR / Bo W

Yes I agree with you Don, about the reasons the shadow detail and highlight detail are preserved. As you said, yes, I do like having a say in the matter, which is what linear offers.

You asked about a comparison-- it's a bit tough because it's hard to judge 'accurate' without being present at the scene, but here's a portrait of my friend I took; you should be able to judge accuracy from skin tones; the wall behind him is very neutral-to-every-so-slightly-warm grey in real life.



I decided to do a non-linear conversion so you could see the difference just between the profiles; it turns out I still have to adjust the contrast with TrueColor profiles anyway, so I guess I didn't gain anything.

All files were converted to 16bpp AsShot, no sharpening or processing performed other than what is noted below.

Standard NL - This is a plain old non-linear conversion using the Canon SDK, tagged as AdobeRGB. Notice: The pinkish color cast in the wall. The face is too red.

TrueColor NL + Levels - A TrueColor non-linear conversion, converted to AdobeRGB. Dynamic range adjusted in levels. Notice: The change in color cast relative to TrueColor NL + Contrast! This shows that adjusting the levels sliders can induce colour casts into your images! In this case I think it's quite pleasing, though. I'd compare this to a Fuji Provia look.

TrueColor NL + Contrast - A TrueColor non-linear conversion, converted to AdobeRGB. Contrast adjusted using Contrast. Notice: Very neutral rendition. Best balance of "pleasing" with "accuracy". I'd compare this to a Fuji Astia look.

TrueColor NL - A TrueColor non-linear conversion, converted to AdobeRGB. No adjustments. This is 'what the sensor recorded'. It's not exciting as it is, but it serves as a very nice stepping stone to either of the two other final images, shown above.

Let me know what you think,
Brad

Don Lashier said:

bradley phillip said:

1. 2 I'd like to use linear conversions to as to preserve as much

shadow and highlight detail as possible.

Click to expand...

But the reason linear conversion preserve shadow and highlight
detail is because they give up some mid-tone contrast. You can't
have your cake and eat it too. But the thing is, as I'm sure you're
aware, is that you can then decide in PS what the trade-offs are
for a particular image and adjust it accordingly.

AFA color accuracy, imho the standard canon non-linear conversion
gives more accurate colors although I sometimes prefer the linear
color result artistically. But I haven't tried the true-color
profiles. Maybe I will. Do you have any comparision shots processed
both ways?

• DL

Click to expand...

Oh, that's not what I wanted to hear!

Well let me roll it around in the back of my head. I'm going to be fairly busy over the next 8 days, so I might be scarce, but if I come up with a workaround, I'll see if I can post soemthing.


Brad

Bo W said:

Brad,

It seems as I have to upgrade to PS7...

The (only) Options button in the PS6 Curves dialog applies to the
Auto function and is visible when you press the Alt key. I forgot...

Unfortunately the only options available here is to set white and
black points.

BR / Bo W

Click to expand...