Gallery Still Not Matching Red Channel

I'm adjusting the reds on a node stack using curves - hue v sat. I'm not getting a matching still grab in the gallery and that is making it difficult to scene match. I noticed this behavior in V17.something but 18 came out before I had a moment to post about it. I'm using V18.0.4 Build 5 on a Mac v12.6 with a Radeon Pro Vega 64 16g graphics card.

See attached for node stack and 2 still grabs of the gallery preview and the image that was grabbed that has higher sat in the reds. Ideas on whats up?

Thanks for any info.

Is it possible there's a background cache going on, and for whatever reason the cache is changing color? I have seen it change level between play and stop under some situations, but it's subtle.

Turn the cache off and see what happens. Also, are you using any color manager or integrated LUTs? If one output is going through a LUT but another is not, you can see discrepancies that way.

The Order of Node Operations can also affect what you see.

I'm starting to feel like it's an order of nodes. I'm seeing the same thing on another clip with the blue channel.

My render is set to none.

I guess I'll start turning off nodes until I can isolate whats causing is. It does seem odd that the gallery still is the only thing effected. If I apply the settings to another slip from the same interview and camera, it matches fine on the timeline so it's something not right in the capture of that still image.

Here we go agin. A still gallery grab with no effects done and a toggle with that same grab reference from the Gallery. Crazy drop in the red channel. Is it my computer graphics card? I see it in both the monitor output also.

Clean Shot_1000.png (553 KiB) Viewed 318 times

Gallery Reference_1000.png (576.29 KiB) Viewed 318 times

With a little testing from other clips it appears to be a change in the black level.

Whenever I suspect there's a problem like this, I'll grab SMPTE bars from the Generator Effects on the Edit page, drop it on the timelime, then make it a Compound Clip (so it's a piece of media). Then, go to the color page, look at Bars on scopes, and make sure the level is OK. Grab a still, and then wipe between Bars and the still of Bars. It should be absolutely identical and the scopes should not change.

If there is a change, I suspect a color management issue.

Turns out to be the Intel chip set in my old ass computer... Time for an upgrade!!!

Stop the presses! When changing out the computer we saw the SAME drop in level. So we started matching up colour management and other settings to see if we could narrow things down further. And as usual, it's a check box.

In the project settings>colur management>broadcast safe selection, turning off any safe modes directly effects the accuracy of your still grab and the timeline play back clip. This should not happen but alas, there you have it. It would appear that all you people don't use broadcast safe for your output cuz NO ONE has mentioned this to my knowledge. There are certainly several areas in export of shows to introduce a level legalizer but doing it at the Resolve point of export is not working properly.