In order that I may get more accurate colour rendering from my images I have created ICC/ColorSync profiles for both Linear and Processed raw mode. The latter is reasonably easy to achieve, the former took a lot more time and effort. The software used to create the profiles discussed in this essay was Pictographics inCamera Professional and the test target the GretagMacbeth ColorChecker DC. This combination is extremely powerful and VERY flexible. With inCamera Professional the profiles can be fine-tuned after they have been created. The extent of this fine-tuning includes the ability to obtain better neutrality, increase or decrease the saturation, contrast, brightness, etc. A comprehensive review of various Pictographics products will be published on this site sometime late August. In the meantime further information on Pictographics products can be obtained by clicking the logo below. A fully functional demonstration version of inCamera Professional can be downloaded. Whilst the ICC/ColorSync profiles cannot be saved for use outside of inCamera Professional it's possible to see their effects and even edit them. A GretagMacbeth ColorChecker DC or ColorChecker chart will also be required. Pictographics are also running a summer promotional price on their software, so this might well be the time to consider buying purpose designed software.

From the images shown below it should be pretty obvious that the application of a custom created ICC/ColorSync profile has significantly improved the colour rendering of all the images.

Both the linear and processed raw mode profiles are best suited to images captured when using Custom white balance, although they also seem to work reasonably well with the Auto white balance mode. However, it is rare for a profile created for custom white balance mode to be truly accurate with the two preset white balance modes; a dedicated profile would normally be required for these. In all of the examples shown below I have used the appropriate linear or processed raw mode profile created for custom white balances images so the daylight and cloudy balanced images will not be at their best.

 

1a. Processed Raw Profile - Automatic White Balance	1b. Linear Raw Profile - Automatic White Balance
2a. Processed Raw Profile - Daylight White Balance	2b. Linear Raw Profile - Daylight White Balance
3a. Processed Raw Profile - Cloudy White Balance	3b. Linear Raw Profile - Cloudy White Balance
4a. Processed Raw Profile - Custom White Balance	4b. Linear Raw Profile - Custom White Balance

 

It should be noted that none of the images have undergone any manipulation or sharpening. They were imported into Photoshop, assigned the appropriate D30 profile and converted to sRGB for web display.

In comparing images 1a through 4b it should be clear that the foliage in both Processed and Linear images is a reasonably close match for each pair. The Canon Processed images show a slight overall increase in saturation with the red petals looking slightly unreal when compared to the Linear images. The Auto white balanced images are the most inaccurate, especially the lower pink Dahlia. The very large area of single colour towards the centre of the image (sensor measures central area only for white balance calculation) is the most likely culprit. So the sensors bias towards the centre of the image, which in this case is green foliage is resulting in a blue tinge throughout the image. It should also be remembered that it isn't possible to accurately profile the camera in Auto white balance mode as each image will have its own unique colour balance based upon the subject in the centre of the frame.

The images captured using the "Daylight" setting are a reasonably close match to the real scene. The "Cloudy" white balanced images are less accurate with a slight warm tone. The optimal image is without doubt Image 4b - Linear Raw Profile applied to a Custom white balanced image with Image 4a coming a very close second. With Image 4b the colour of the foliage and flowers is getting close to being almost indistinguishable from the real thing - trust me! Image 4a suffers from slight over saturation but this results from the Canon software clipping the end points much to fiercely and so can't easily be fixed.

So what have we learned?

• Don't assume an incorrect colour is down to the wrong white balance setting, it VERY probably isn't.

• Choose Raw mode for capturing images as it allows us to fix a wrong white balance setting after the fact.

• Custom white balance is the optimal choice. We should consider creating our own series of preset values using the white side of Kodak 18% grey card (or similar) as the target..

• When converting the Raw format image to Tiff format toggle between each of the various white balance options and choose the image that appears most neutral.

• For the most accurate colour rendition we should consider buying or creating our own ICC/ColorSync profile for the EOS D30 that is designed for use with Linear Raw mode. If this proves difficult, buy or create a profile for Processed Raw mode. It won't correct the D30's worst failings but as the images above show it's better than nothing.

Footnote:

As indicated above creating an accurate profile for Linear Raw mode images is not a simple task. However, there is no doubt that the results obtainable from the EOS D30 when using such profiles makes the task worthwhile. The accuracy of colour rendition and the ability to "hold" highlights that the Canon software "blows" has the potential to make failed images useable again. It isn't the case that a "one-size fits-all" profile will work with Linear Raw mode. Likewise not all images will benefit to the same extent from its application. In particular, I have found portraits with heavy shadow areas (my poor lighting technique) are better handled by Canons own Raw to Tiff conversion algorithms followed by the application of a profile created for this mode.  The final result of this may not be an optimal image in the sense that contrast and saturation will be slightly less than normal. The image will therefore require more work than Canons own processing of the image - but extensive colour correction is a rarity and the final images are significantly better.

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