Colour-blind help needed

[Bub-les]

My son who is colour blind red/green has recently taken up photography. He's doing OK too! He has come to a problem as he finds it difficult to post process. He seems to end up with most things having a green cast
quote from an email from him "I was informed that this had a green cast to it, and it was suggested to me to get
the WB off the background. And that is the latest one that you commented on. To be
honest I can't tell the difference unless the 2 images are side by side and then it
takes a fair while to see it. I'm going to have to investigate ways to check WB
either using the RGB figures for the colours or some graph or something.

This really is where I struggle."
Unfortunately the photos he's referring to are not wildlife ones nor are they on WAB
Hope someone can help.
Barbara
Any ideas would be appreciated

[BruceP]

He needs to be correcting his colour balance "by the numbers". By this I mean using the eye dropper tool in photoshop (or equivalant programme) and recording the RGB values on his white and grey points. Possibly the most detailed description i've read on doing this is in the book "Photoshop LAB color" by Dan Margulis ISBN 0-321-35678-0. Although this book concentrates on the benefits of working in LAB mode rather than RGB, the principles are the same.

Using this technique, his colour blindness won't be a problem.

[eeyore]

also a green cast would suggest that he is using the WB set to sodium lighting under natural light - i would tend to suggest that he either selects auto wb or sets it to shade - the wb may end up to cold (blue) or too warm (yellow) but gren casts are not normally encountered using any daylight wb setting.

[Hobjob]

Eeore and BruceP have it right.

Two additional points

1. I very rarely re-set White balance or colour balance.
Is he fiddling too much perhaps? Just boosting saturation
(which compacts do in-camera) may be enough.
(sunsets and sunrises excepted)

2. Concentrate on B & W as an art form.
I read somewhere that red/green colour blindidness
(which is the most common by a long way) often
poriduce striking images this way.
But there are good ways and bad ways of turning colour
photos into B & W.
I've been told by my daughter, but forgotten, so could
find out if no one comes up with an answer.

She finds all her brides love a few B & W photos.
(and , horro of horros, those ghastly B & W with
coloured falling rose petals!)

[Bub-les]

Thanks for your help so far. I have passed your thoughts on to my son. He says he's going to work on the numbers idea and see how it goes. I don't think he needs to do much more than learn how to read the in camera histograms and try to get the in camera settings as true as possible cutting down on post processing. He has a Pentax K10D. As far a B&W is concerned I haven't suggested that to him yet!
Barbara

[BruceP]

Here another slightly different way that i've copied from a photoshop site:

No matter how hard you try to really tune into that white reading or lock in that exposure, every photo can benefit from at least a little bit of color correction. Here's a great tip I picked up from Scott Kelby's Photoshop CS2 for Digital Photographers.

1. Open any RGB photo you feel could benefit from a color correction.

2. Select Image>Adjustments>Curves. Now, if you've ever used Curves before for color correction, you know that the best way to do this is by using the black eyedropper tool to tune into the darkest area of the image (the shadows), the white eyedropper to tune into the brightest area of the image (the highlights), and the grey eyedropper to tune into a good midtone. The only problem with doing this as-is is that Photoshop has predetermined which colors it will use to define these areas, oftentimes resulting in even more of a color cast than we had to begin with. What we want to do is give the Curves dialogue some good, balanced colors to define our shadows, highlights, and midtones. So, moving right along, then.

3. Double-click the black eyedropper in the Curves dialogue (located lower-right). This will bring up the familiar color picker where we will enter values in the R, G, and B (Red, Green, and Blue) fields. Enter 20 for each field. This should give you a Hex value of #141414. Click OK.

4. Double-click the white eyedropper to the far right of the black eyedropper. Again, we will enter values for the R, G, and B fields. This time, enter 244 for each, which should give you a Hex value of #f4f4f4. Click OK.

5. Finally, double-click the grey eyedropper located between the black and white eyedroppers. Enter 133 in your R, G, and B fields, resulting in a Hex of #858585. Click OK.

6. Now that you've programmed your color preferences for shadows, midtones, and highlights, you will use your eyedropper tools primarly when color correcting using Curves. Your job, now, will be to determine which are the darkest and brights areas of the image, as well as the midtones, then, using the respective eyedropper, click there. In case you're having difficulty determing specifically where these areas are in your image, continue on. If not, then just skip down to Step 13.

7. Close the Curves dialogue. Photoshop will ask you if you want to save the new target colors you entered as defaults. Go ahead and click OK, so you don't have to keep entering them every time.

8. Create a New Threshold Adjustment Layer (Layer>New Adjustment Layer>Threshold).

9. Once the Threshold dialogue appears, move the slider all the way to the left. Your image should now be completely white. Start moving the slider slowly back to the right. As you do, small traces of black will start appearing. The first and most prominent of these areas are the truly darkest areas of the image.

10. Close the Threshold dialogue and grab your Color Sampler Tool (it's part of the Eyedropper Tool's flyout menu in the Toolbox). Click on the black area in your image, and you will see that Photoshop has now added a small crosshair with a number 1 beside it.

11. Double-click the Threshold layer icon to bring the Threshold dialogue back up. Move the slider all the way to the right. The image should now be completely black. Start moving the slider to the left and, yep, you guessed it. Those slight traces of white are the brightest highlights of your image. Using your Color Sampler Tool again, mark the most prominent white area. A small crosshair marked by a number 2 will be placed.

12. Click OK on the Threshold dialogue, but then discard the Adjustment Layer altogether. You were only using it for reference purposes, and those two invaluable crosshairs are still in place. Open the Curves dialogue back up.

13. Select the black eyedropper tool. Move your cursor outside the Curves dialogue to the darkest part of your image. (For those who hung out with me through steps 7 - 12, it's the one marked by the first crosshair.) Click here, and you will already see a change in your color quality. What we've basically just done is reassigned our new neutral shadow color we created to the shadows in our image.

14. Switch to your white eyedropper and click on the brightest area of your image (crosshair #2 for you 7 - 12ers). You will see the highlights of your image adjust accordingly.

15. Now that you've adjusted your shadows and higlights, you're ready to tackle the most difficult part of this tutorial: finding a midtone. For those images that actually contain a grey shade, this isn't a problem at all. Just use your grey eyedropper and click on something that's grey. Unfortunately, not every image contains a grey shade, so not every photo will be able to have it's midtones adjusted...until now. Want an even cooler extra step? Then read on, and I'll show you a super-secret trick to finding a neutral grey to your image. If not, then, well, you're pretty much done. Except for one final step, which is to simply grab your color curve line at dead center and pull it towards the upper left corner of the dialogue. This will help brighten the entire image, giving a nicer, less gloomy effect, and pulling even more color out of the image.

If you're happy with this tutorial as-is, then fine. Go on ahead. I'll show the true believers the really cool neutral grey effect without you. Seriously, go on. We'll be fine. Go back to your game of Halo. We'd hate to keep you.






Okay, guys, here's the cool trick I was telling you about for finding a neutral grey image somewhere in your image.

1. Create a New Layer.

2. Choose Edit>Fill. Fill the new layer with 50% Gray.

3. Change the Blending Mode of the new layer to Difference.

4. Create a New Threshold Adjustment Layer and drag the slider all the way to the left. Slowly drag the slider to the right, and the black areas that start to come back in are your true midtones as opposed to the shadows. Mark this area with your Color Sampler Tool as we did before.

See? That simple. Hope you enjoyed. Have fun with it. The more you use this method of color correction, the easier and more effective it becomes.


Hope this all makes sense.

Bruce

[BillyPilgrim]

I'm also colour blind on red/green. I used to muck about with the colour settings in Photoshop but just ended up being confused and having to enlist the help of the wife to tell me if the colours looked right. They hardly ever did!

So nowadays I shoot RAW to avoid having to set the white balance. I sometimes choose 'Auto' white balance in Lightroom before converting the photo into a jpeg. This usually warms the image up a bit.

Then I open the jpeg in Photoshop and click on Auto-Levels. Sometimes I undo the result but it 90% of the time I keep it.

After that I apply some sharpening and noise reduction before saving the result.