Lightroom RGB Percentage vs Photoshop RGB numbers

Trying to get my Lightroom refined images as close as possible to Photoshop optimized versions, I discovered that the Lightroom RGB percentages do not match Photoshop RGB numbers.

Lately I have been finishing my underwater images in Photoshop, as Lightroom does not offer the amount of color correction control I waned.

However, reimporting my corrected images into Lightroom, the black point RGB numbers were not  consistent with my Photoshop RGB numbers.

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Be Careful with Scanner Auto Settings

Using scanner auto settings can cause problems when scanning images. Turning off the auto settings, and using manual settings can make image correction easier and more accurate.

The Problem

I was recently scanning some images using my CanoscanFS4000US slide scanner (Canonscan FS4000US ICC profile).  After scanning the images and assigning the custom profile, a number of slides were exhibiting saturated highlights.

autogainonimagezoom1Figure 1 – Saturated highlights

Figure 1 shows the ear of a Koala bear. You can see an area of red pixels around the bright centre of the ear.

I had not seen this in the past and it had me confused for a while, as I thought using a custom profile was supposed to correct this.

With a little investigation I was able to determine my problem was the scanner settings.

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Canoscan FS4000US ICC Profile

I decided to get serious about profiling my Canoscan FS4000US slider scanner, due to having several years of slides from the period before my switch to digital.

My Canoscan FS4000US scanner is a couple of years old now (costing around $1500AUD when new), but provides high resolution images from slides and negatives.

For years I have wondered about what profiles to apply to my scanned slides. I tried hunting around on the web to see if there was some kind of boxed ICC profile available, but could not find anything.

For a while now my standard procedure has been to import the images from the scanner into Photoshop, assign the sRGB profile, and then convert to my default workspace profile of AdobeRGB. I have tried assigning AdobeRGB profiles directly to the scanned images, but it resulted in over saturated images.

Noticing my images were slightly washed out after conversion, I began to question how much color information has been distorted in the workflow process.

Producing the scanner ICC profile

The first step was to purchase a couple of IT-8 slide targets from Wolf Faust ( They were well priced, supplied very promptly, and good quality. Wolf has lots of interesting stuff on his main site about color management.

To produce the profile, I then downloaded and purchased the Profile Mechanic software from Digital Light and Color, which made the process of generating a profile very easy, and gave me the ICC profile required.

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Samsung 2243BWX Monitor – Part 2

I just remembered today that the Samsung 2243BWX monitor I purchased recently came with a pre-made (or ‘canned’) ICC profile.

For interest, I decided to compare the canned profile with the Spyder 2 colorimeter ICC profile using the Chromix ColorThink software.

The 2D view of the profiles show the canned and measured profiles follow each other quite well, except in the area of blue to red transition. It also shows they are off-set slightly.

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Samsung 2243BWX Monitor

I have been working on a windows laptop for a while, and spending a lot of time at present in front of it, decided to look at an additional screen.

Ideally I would have liked to purchase an Eizo screen, but they aren’t within my budget just yet, so I looked at various screens available around town.

Settled on a Samsung 2243BXW due to price, and the fact that Samsung is one of the four companies that make all of the LCD monitors in the world.

The thing that I like about the screen is the 300 cd/m2 brightness. This blows away my laptop, and interestingly this does not seem to be a specification typically listed with laptops.

The first thing I did on setup, was color calibrate the monitor using the Pantone Spyder2 to compare it with my HP laptop.  After some experimenting I discovered Windows does not support ICC profiles on multiple screens, unless separate video cards are used.

The other thing I noticed is that there is a very narrow viewing angle (around 5 degrees) for the correct colour viewing. Moving slightly to either side (or up and down) and a red hue begins to appear at the edges.

After calibrating the screen, I checked the ICC profile using Chromix ColorThink software. This software is brilliant for understanding color issues, allowing visual 2D and 3D rendering and comparison of color profiles.

Results of the calibration show the Samsung 2243BWX screen has a color profile that approximates sRGB. (The Eizo screens quote 95-98% of AdobeRGB1998).

The other result is that the laptop screen gamut is smaller than sRGB, and this explains why images viewed on a laptop in a non-color managed environment appear faded. (I have had a couple of friends confine this effect on different laptop brands.)

This raises an interesting question – If LCD monitors can produce sRGB, why do laptops have a smaller gamut, when they are effectively the same thing?

The conclusion – The Samsung 2243BWX will do me for now, but when I get the funds together, will be upgrading to an Eizo monitor.