Claire - Pro Colour Matching

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A plug-in for the camera RAW image processing program Bibble.
Author: Sean Puckett (seanmpuckett@gmail.com).

Bibble 5 note: This is a Bibble 4 plug-in. It does not work with Bibble 5.

What does Claire do?

Claire allows you to use popular colour reference targets to colour correct multiple images at once. Use a Gretag Macbeth ColorChecker or a QPcard 201 in a lighting reference shot, then use the correction values from that shot to fix an entire session in an instant.

Purchase Professional Version Now

Windows, Linux and Mac versions included in the same download. ClairePRO is now available for Windows, Macintosh (Intel and PPC), and Linux. Claire is useful even if you don't have a colour reference target because it can correct white balance based on a grey card (see below).

ClairePRO: $20 USD

Already purchased, but need an upgrade? Click Here.

If you purchase this plug-in, you do so knowing it is not compatible with Bibble 5. I do not provide installation support for Bibble 4 plug-ins, and in purchasing them you do so at your own risk. Further, I do not guarantee that any Bibble 4 plug-in will be available for Bibble 5.

Sample Output

Process

Isolate Colour Target

claire-target Info

Before Correction

claire-before Info

After Correction

claire-after Info

Portrait

Original, handheld with JPG point and shoot camera.

ClaireBefore-a Info

Claire corrected.

ClaireAfter-a Info

Just how bad is compact fluorescent lighting, anyway? This "difference" image shows just how far off the colour really is, and just how much work Claire has to do to bring it back into line.

ClaireDiff-a Info

Demo Video

Instructional Videos

Instructional videos for different situations are being produced.

Overview

Claire is easy to use and requires very little user interaction.

  1. Shoot a high quality colour reference target in the same lighting you'll use for your subject. This will be your reference image.
  2. Select the reference image in Bibble and drag the crop window to match the target's colour patches, then click "Analyze"
  3. Group select all other images from your shoot and click "Apply"
  4. Done! -- The rest of your images are now colour correct.

If you're using the same exposure for each image (e.g. doing art repro), Claire can also correct the exposure and gamma curve to match your target, so that output is entirely predictable in balance, tone curve, and colour accuracy.

An essential tool for studio, commercial, portrait and any other work where precise colour is needed -- and one-click correction is wanted.

Lighting and Camera calibration simultaneously

Since Claire knows the exact formulation of the patches on your colour targets, it knows exactly how the colours captured by your camera are changed -- not only by lighting, but by the camera sensor, saturation, tone curve and other settings. And with all of this information in hand, Claire can correct all of these defects simultaneously so colours perfectly match the target. So, no matter what lighting or camera you are using, you get exactly the same colour, every shot.

How to Use Claire

Step by step instructions on using Claire.

On the shoot:

  1. Turn off auto white balance on your camera (important). Select an appropriate standard setting, or use a custom white balance. Consistent colour among all images is essential.
  2. Place your colour reference (WhiBal, QPcard 201, or Macbeth 24 patch ColorChecker) in the same lighting as your subjects. Make sure the target is square to the camera so it looks rectangular through the viewfinder. Check the lighting -- the target should be evenly lit and not shadowed by fingers (if being held).
  3. Make an exposure, and check the histogram to see if you are reasonably accurate with lighting. The target should be well lit but not overexposed.
  4. Put the colour reference away for safe keeping and finish up your shoot. If you change lighting significantly, shoot another colour reference frame.

At the computer:

  1. Using Bibble, view the exposure that has the colour reference in it.
  2. Use the crop window to isolate the colour squares of your reference closely. Use image rotation if necessary to make sure the reference is horizontal and square to the screen. Select the type of target you are using in Claire's target drop list.
  3. Click "Rescan" in Claire and note the position of the guide squares. Adjust the crop window if needed so that the guide squares perfectly overlap the target colour squares. Click "Rescan" and adjust the crop window as many times as needed to get this right.
  4. If you see red and blue indicators inside the guide squares, then the exposure of the target isn't right. Lots of blue indicators means your target is underexposed; use Bibble's "exposure" slider to increase the exposure, but not so far as you see dark blotches in the image (indicating channel clipping). Lots of red indicators mean overexposed. Decrease Bibble's "exposure" setting. Important: do not use any other tools (Siggy, Ansel, etc) to adjust exposure! When you get a similar number of red and blue indicators (or you are limited by red clip warnings) the target analysis is complete. Click Claire's "Apply" to set the colour correction for the target image and see how it looks.
  5. Select any other image from the same shoot and click Claire's "Apply" button. You can click "Apply" as often as you like, on as many images as you want (even multiple selections).

That's it.

Claire User Interface

ClairePRO10 Info

Claire is a small plug-in that has two groups of settings: Target Analysis and Colour Correction.

Target Analysis Group

This section is used when viewing the colour reference image and creating a correction analysis.

Target Selection Drop List

The current version of Claire supports the following colour targets:

  1. Gretag Macbeth ColorChecker - 24 patches - viewed under D50 light
  2. Gretag Macbeth ColorChecker - 24 patches - viewed under D65 light
  3. QPcard 201 - 30 patches - viewed under D65 light
  4. Three target grey card - black, grey, white - D65 light
  5. Grey card - D65 light
  6. I will probably release a "Claire card" at some point which will be cheap, sturdy and useful, but I haven't perfected the colour selection yet. We'll see how it goes.

Analyzer On Checkbox

When checked, Claire performs colour analysis based on the crop window settings and the target selection. Anytime this checkbox is checked, the analysis is available to be Applied.

Exposure indicators appear in the target squares when Analyze is checked. This allows you to check the real-world card exposure against the expected exposure of the target patches. Red indicators show overexposed target squares; decrease Exposure. Blue indicators are underexposed. You may see dark reddish blotches in your image if you increase exposure; these indicate channel clipping and inaccurate colour. Reduce exposure slightly until they vanish from the target, even if you get more blue exposure warnings.

Use Bibble's exposure slider (only!) to adjust the exposure of your target card image. If you can't adjust exposure enough, the target exposure is too far off and the colour correction will not be as good.

Refresh Button

Click this button anytime you have moved the crop window to trigger a recalculation.

About Button

Shows the author and version of the plug-in.

Step 2. Apply Correction Group

This group controls the application of a colour correction analysis.

Apply Button

Saves the last correction calculated (even if it was calculated on another image) to the current image. This is sort of like a clipboard "paste" function.

Correction Source Text Box

Reminds you of the name of the file you used to create the colour correction. You can type in this field to create a notation of your own.

Enable Checkbox

Activates the correction that has been applied to this image.

WB Checkbox

Restricts the correction to white/grey/black target patches only. This provides white balance correction without affecting colour saturation or chroma correction. (Maybe you like the colours your camera provides but still need to correct white balance.)

Expo Checkbox

Causes the luminance tone curve of the reference target/image to be applied to the current image. This should not be used unless the current image uses the same lighting and manual camera exposure as the reference image -- otherwise the reproduced tone curve will be inaccurate.

Diff Checkbox

Shows you how much the original image differs from the corrected image. Doesn't show aggregate white balance (which takes place separately from colour correction), so if your colours are already quite accurate, this may just appear to be a greyscale image.

Notes

Never: Camera Auto White Balance + Claire

If you intend to use Claire, don't use auto white balance. If your camera isn't capturing consistent colour from image to image, Claire can't fix it. As far as Claire is concerned, consistently BAD colour is just as easy to work with as consistently GOOD colour. It simply must be consistent for every shot in the series.

Never: Bibble White Balance + Claire

Claire has its own white balance algorithm. Let Claire manage all colour correction and you'll get a much better result.

Never: Tweak reference images away from your Defaults

Don't try and set white balance or adjust shadows/highlights or any other settings other than exposure on your colour target reference images, unless you're planning on making those exact same settings on all of your other images.

Claire corrects differences in colour, not absolutes, so if you change the starting point of any of your images, Claire will still correct colour assuming the image needs the same corrections as before, which may no longer be the case.

If you're not getting accurate colour, then before you start a support issue, "remove bibble settings" from both reference target and the troublesome image, then create a new analysis and reapply it. See if the problem goes away -- if it does, then a settings conflict was the cause.

Okay: Autolevels, PC, NN, and many other tools.

You can use autolevels and/or Perfectly Clear and/or Noise Ninja without affecting Claire's analysis or correction. You can also use curves and many other tools because they are applied after Claire's processing.

Trouble?

Some notes on how Claire can interact with Bibble to produce results that aren't quite what you wanted.

Image gets darker!

When Claire does white balancing, it scans the image histogram to make sure that no channels will be clipped after applying the balancing algorithm. If channels would be clipped (e.g. bright blue in incandescent lighting), the image is darkened so detail in those channels isn't lost. Use an exposure slider in your favorite tool to brighten the image up again (Siggy is a good choice as it won't clip).

Blown out clouds turn yellow!

If you've got pure white in an image (generally due to overexposure) and yet the image needs significant white balancing, then pure white will take on whatever colour cast the balance provides due to Claire's "no clip" white balancing. Use a clipping exposure slider (Bibble's built in one works) to increase exposure to blow-out your highlights again; if you like them blown.

Image loses contrast!

If your camera is contrasty (point and shoot, for example) or you have a high contrast tone curve set, Claire will probably flatten it out somewhat to restore a reasonably accurate luminance profile of the target grey patches. That's what Claire is supposed to do; it's not a bug.

HOWTOs - Special situations

Any more requests?

White balance without a reference target!

Forget your target? Or didn't have one for that shoot? Well, maybe Claire can do some good for you anyway.

  1. Select a "1 Patch Grey" target in Claire.
  2. Use the crop window to select something in the mid- to light-grey range. The bigger, the better, but it doesn't have to be evenly lit. Just ... greyish.
  3. Analyze it with Claire.
  4. Apply these correction settings to the rest of your images. Your whites should now be whiter.

Art Repro Captures

Here's how I do it.

In the studio

  1. Set up lighting, do in-camera custom white balance based on white backer board at easel.
  2. Place reference target on easel, set manual exposure mode on camera.
  3. Find exposure that correctly renders target in the histogram but leaves a little headroom for superwhites.
  4. Do not change exposure again. Photograph all artwork without changing exposure.

At the computer

  1. Locate reference target with correct exposure, analyze with Claire.
  2. Select all artwork images, click "Apply" then "Expo" checkbox.
  3. Review images individually, checking for good colour and exposure.
  4. Everything should be fine.

Legal

Claire is copyright 2007 Sean M Puckett, all rights reserved. Claire may not be distributed except via direct download from its homepage.

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