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RGB weights for Astronomik Type iic filters


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If no one answers, you can figure it out as follows:

"It requires an 18% grey card, available at most camera shops, and a full or nearly full moon. You make images of the card of equal exposures through each filter using the moon for illumination. You import each of them into Photoshop or whatever post processing software you use and merge them to form and RGB image. It should look pretty much like the grey card although it might be a little lighter or darker. Then you measure the values of each channel in one spot. The Color Sampler tool in Photoshop is great for this. A little simple math with those values will determine the correct ratios for each filter in a given camera."

Source:  http://www.cloudynights.com/item.php?item_id=2114

Cheers,

Paul.

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If no one answers, you can figure it out as follows:

"It requires an 18% grey card, available at most camera shops, and a full or nearly full moon. You make images of the card of equal exposures through each filter using the moon for illumination. You import each of them into Photoshop or whatever post processing software you use and merge them to form and RGB image. It should look pretty much like the grey card although it might be a little lighter or darker. Then you measure the values of each channel in one spot. The Color Sampler tool in Photoshop is great for this. A little simple math with those values will determine the correct ratios for each filter in a given camera."

Source:  http://www.cloudynights.com/item.php?item_id=2114

Cheers,

Paul.

Thank you Paul, I will give it a try  time I set up.

Regards,

A.G

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I'd advise taking a 1:1:1 weighted image into Pixinsight and then running DBE on it. Of all the colour balancing methods I've tried, this is most certainly the one. I use it on my images and it also works on the most insanely light polluted images which I'm sometimes involved with in processing. Given the varied levels and spectra of light pollution I very much doubt that any one weighting will be universally applicable.

Olly

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I'd advise taking a 1:1:1 weighted image into Pixinsight and then running DBE on it. Of all the colour balancing methods I've tried, this is most certainly the one. I use it on my images and it also works on the most insanely light polluted images which I'm sometimes involved with in processing. Given the varied levels and spectra of light pollution I very much doubt that any one weighting will be universally applicable.

Olly

Hi Olly,

Now that I have a licensed copy of PI, I might as well get used to its features.

Regards,

A.G

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Would you need moonlight?  Presumably using a grey card in sunlight would allow you to calculate white balance (the light source is, after all, G2V!)

How is the grey card's greyness going to be defined? I'd have thought, though, that a neutral density filter filtering sunlight ought to work. I take the main point. Perhaps the professionals have already gone into this?

Very interesting!!

Olly

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