RAW vs White balance

Started Nov 20, 2006 | Discussions thread
edhannon
edhannon Senior Member • Posts: 1,761
Re: RAW vs White balance

The idea that WB may effect RAW files caught my attention. It would be great if I could reduce red channel saturation in tungsten light by changing white balance.

So I wanted to see it myself. Unfortunately I have a *istD and the histogram Java program is for those models that compact the Raw file by using the top 4 bits of the 16 bit word.

It had been a long time since I have been able to play with writing software, so I started a background project to implement the histogram routine in MS Excel QBA. This way I would have more flexibilty in analyzing the results.

It is hard to stop once you get going on a project like this ... so now I have an Excel spreadsheet that has QBA modules that will not onlly draw historams for the *istD but also create tone curves from a series of "white wall" images. I plot the mode of the values in the file. This is the most common value.

I did a white wall test early this morning before the sun came up so I could use pure tungsten light. The results are below.

The first curve is from images shot with white balance set to daylight and the second with white balance set to tungsten.

The differences between the curves is very small. What difference there is I atribute to changing light conditions -- the sun was coming out.

Clearly changing white balance will not reduce Red saturaton in tungsten light.

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