D90 white balance/colour balance?

Started Apr 11, 2013 | Questions thread
OP Penny123 Regular Member • Posts: 357
Re: D90 white balance/colour balance?

pixd90 wrote:

You should have used a white card. What is white?  It’s a RGB of 255,255,255.

I just took a picture of my kitchen with a white card. Opened it in photoshop and used eyedropper to get a reading of R-233,G-230,B-200. Opened levels, used white point and clicked on white card. If I had orange lighting the reading would be different.

Took new reading of white card and it was 255,255,255. Photoshop added 22 to red, 25 to white and 55. Based on this it than used an algorithm to adjust every pixel to a different color.

So adjusting white balance does adjust color. If you have to adjust white balance without a card you can set your D90 to live view. Hold the WB button and turn the back wheel to get waht you want than take it off WB. Remember to mave it back to auto. You will also come acroo "K"-kelvin, you use the front wheel to adjust color temperture.

I find adjusting picture control to your preference and using auto WB works very well. when the lighting is difficult i use the live view procedure or white/grey card.

I am not sure what your level of expertise is, so I will try to explain it as best I can so you can understand the concept without getting into the intricate details. White balance has a direct impact on color. Color is a pigmentation represented as a mixture of RGB (red, green & blue) It’s like mixing paint. Each color has a value ranging from 0 to 255. This table shows you the mix of RGB values for different colors http://www.rapidtables.com/web/color/RGB_Color.htm

Let’s say you walk into a room at night with blue curtains, you see black because there is no reflection of light. If you open the lights you see a shade of blue. If during the day and open up the curtains you will see a different shade because of the amount of light.  Now go in at night and shine a flashlight with a yellow gel in front of it, you will get a different shade varying with the power of the flashlight. The colors we see are simply a degree of how much of the color present in light is reflected.

You take a picture inside an empty restaurant where the lights reflect an orange tint. Your friends arrive and a picture is taken all their faces have an orange tint. The first one may be artistically correct but don’t think you want friends with orange faces. White balance would than be used to remove the orange tint by adjusting the color of the pixels.

I am not a complete newbie but I don't have a broad understanding of all the real technical issues.

Thank you for taking the time to type us such a detailed reply.  I was out again this evening before I read this, it was about an hour before sunset and a miserable type day and dull.  I took a selection of shots and not many looked right.  The landscape ones seemed ok but the dog ones looked rather washed out again.  I have since tried the live view options as you suggested and although inside I got a feel of what to do so I can try that tomorrow.

The weather is looking better for tomorrow so hopefully I can get out testing again, these miserable days are not the best for trying out new technology.  I think I will also take my D40 out with me so I can get side by side comparisons to what is lacking if anything.

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