When I open a raw file with Demosaicing set to Method=none and zoom to maximum to see the pixels, I see the expected RGBG pattern – except all the ‘blue’ pixels are black.
However, if I go to the Exposure panel and press ‘Reset’, the blue pixels light up and I see the expected RGBG display.
Any thoughts on why the Exposure/Reset button needs to be pressed in this situation? I wasn’t able to determine what Reset does exactly (eg., resets to what?).
This is with RT 4.2.1234 on win10.
Which blue value is shown below navigator for these pixels?
All zeroes (in all three columns, ie., RGB, HSV, Lab).
Here’s what I did just now:
Then if I press Exposure: Reset, the black pixels turn blue.
Yesterday I did a range check (using homebrew s/w, maybe flawed) of a PNG exported from the ‘black’ version and the ‘should-be-blue’ pixels apparently have a value of 0…1 (so there’s apparently a value of 1 in one of the blue pixels somewhere, but none that I’ve found using the mouse).
I tried loading Default, changing to Method=none, then editing the pp3 file to set Exposure, Auto to false, then reopening the file – still black. I think Exposure->Reset does more than just set Auto to false, so maybe it is affected by one of those other Exposure settings.
If you want to view the pixels before demosaic (using ‘none’) you should not apply default profile, but neutral profile. Default profile includes auto exposure which changes ‘Black’. This change of ‘Black’ is responsible for the blue pixels getting black. Just try it. Instead of Reset set the Black slider to zero.
Thanks, that worked!
I was confused by the histogram – it still shows strong blue content in the 64-128 quarter of the chart, even with the blue pixels appearing as black and measuring zero under the mouse.
Moving the black slider slowly shifts the blue histogram, as expected, but there seems to be value for the black slider (around 272 with my test image) above which the blue pixels suddenly change from black to blue. I guess that’s related to the max blue values in my image but I would have expected the blue histogram to shift off to nothing at that point too. Why would the blue pixels suddenly go from black to bright at a particularly black slider point?
I guess I don’t understand the RT histogram (and/or the black slider). In Photoshop, the histogram matches what’s on the screen; if the blue pixels were black in PS, they’d be zero on the histogram too; shifting the black point up in PS causes the histogram to shift left, and off entirely when the black point exceeds all content.
By using the Blue channel preview, I noticed that the red squares (in demosaic=none mode) have some blue content; I don’t know if that accounts for the histogram.
Anyway, thanks for helping get me beyond the problem I was having in the original post! Much appreciated.
That’s because for whatever reason there is some blue in the red pixels. Seems to be a bug in demosaic ‘none’…