Light Pollution filter setting for Color module

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jhart
Posts: 27
Joined: Wed Aug 26, 2020 10:08 pm

Re: Light Pollution filter setting for Color module

Post by jhart »

Thanks for the info almcl.

I think the question becomes: Is there a way to separately wipe OSC Luminance and OSC RGB data sets (including pre-Wipe bin and crop), load them into their respective channels in Compose, and process those channels in the regular way with the post-Wipe StarTools modules? As mentioned above, loading the separately wiped L and RGB files -- that are saved in Tiff format by ST -- into the respective L and RGB channels, results in ST thinking those files have not been wiped and shutting down the operation of the Color module.

Jeff
Mike in Rancho
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Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: Light Pollution filter setting for Color module

Post by Mike in Rancho »

Hi Jeff,

Setting aside the acquisition and composition theory here (not really sure I am on board with this disconnect between luminance and color for broadband targets), in the descriptions above I think I see a couple issues that you could be getting snagged on here...

I've used pre-Wiped tiff saves a number of times when needed, in fact I've even split OSC into mono RGB (or if duo NB extracted and combined into Ha and OIII).

All depends on your plan here of course. Maybe it was mentioned and I missed it, but I get the sense this is OSC and your are not extracting. So, an LP-filtered set you will be using for L, and the other is full OSC color being wiped as is?

Indeed you will end up with everything monochrome if loaded normally, or composed with defaults, on that OSC file. I believe the remedy is to choose the composition method of RGB, RGB (legacy), and run your pre-Wipe on that. That little snafu was recently discussed and Ivo reminded us of the legacy compose in order to float the colors through and avoid where ST goes into mono (since we all forgot lol), but I can't dig that thread up despite searching around. Anywho, I think that legacy compose will do the trick. After Wipe, save it and you should get your linear color file which can then be recomposed when you are ready. Avoid use of AutoDev/FilmDev and/or make sure ST reverts it after the Wipe - which off the top of my head it may do anyway.

You can indeed do this on cropped and binned data as well (sometimes needed for Wipe of course, unless you mask stuff out), just make sure to use identical crops and bins for the sets you are pre-wiping. You might want to do a dry run to get those particulars (because you would probably use AutoDev for that) and then start again for real.

When you get to color, I thought the "no Wipe" warning was just a little slap on the wrist and didn't stop you from going forward? Regardless, you can run Wipe yet again on your final composition. If not needed, just back off the aggressiveness or even zero it out, much like the NB preset. That way you should get little to no gradient removal, which you have already done, but should still establish the color channel floors - though with a single OSC file I would presume that already done during the pre-Wipe? :think: But anyway, the Color module won't yell at you. :D

Hope there's something handy in all that!
jhart
Posts: 27
Joined: Wed Aug 26, 2020 10:08 pm

Re: Light Pollution filter setting for Color module

Post by jhart »

Hi Mike,

Thanks for the ideas to try.

I am using an OSC camera. I am trying with a Luminance stack with the L-Pro filter and a stack for color with the IR/UV filter. I save each after wipe (being careful to use the exact same crops; didn't bin). I did not stretch with AutoDev or FilmDev before saving. I loaded the resulting TIFF files in Compose. I didn't split out the color channels but loaded the color stack in each of the R, G, and B channels. I saved Compose using L,RGB. I retried the process with the RGB,RGB (Legacy) and still got the no-wipe warning in Color module and the mono image there. (A question: how does StarTools use the separately loaded L file with that Legacy mode?).

Maybe I misunderstood. Are you recommending that I do not use Wipe until after I combine the files in Compose? I wiped the L and color files separately before saving them, attempting to use a different level of wipe on L than on color as Jochen suggested. Or are you suggesting that I load the color stack initially with Compose and save it with that Legacy mode before cropping, wiping and saving it (and then putting it in Compose a second time as R, G, and B, along with the L stack loaded as L)?

Jeff
Mike in Rancho
Posts: 666
Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: Light Pollution filter setting for Color module

Post by Mike in Rancho »

Sorry Jeff, I think I left things too confusing.

I would say more like your second paragraph... :think:

So, with your original stacks, one OSC L-Pro and one OSC full color, I would do the following if you feel you need to run separate Wipes:

Open the L-Pro file. Center option should be fine. It doesn't matter if this one saves as mono, that's the point anyway. Crop and bin as needed to your known specifications. Run Wipe, and keep. Save as a tiff, name it L-Pro Wiped or something like that. Occasionally I will even put the gradient aggressiveness used in the file name, so I can try different things later.

Compose the color file, same file into each of R, G, and B. Use RGB, RGB legacy. I believe you must choose left-option Linear, so that your save ends up in color. Crop and bin to the same specs. Run Wipe as needed for this file, and keep. Save.

Now, compose using the pre-Wiped L-Pro file as L, and the pre-Wiped color file into R, G, and B. You can try mode L, RGB first, and keep. If there's too much disconnect you could always re-try as L+Synth L, and even alter up the weighting, to feed in a little detail from the color stack. Cropping and binning are of course already done so you should be good there. Run Wipe, if you don't want the color warning later on, and to see if you need another bite at the apple for gradients. If not, just take the aggressiveness slider down to zero, or hit the NB preset. Review edge behavior if needed. Keep.

Proceed from there.

I hope that works... :? :D
jhart
Posts: 27
Joined: Wed Aug 26, 2020 10:08 pm

Re: Light Pollution filter setting for Color module

Post by jhart »

Hi Mike,

Thanks for the detailed clarification. One question, why do I need to run Wipe and save the L-Pro Luminance and the composed RGB,RGB(Legacy) color stacks if I will be combining the pre-Wipe versions of those L and color stacks in Compose?

Thanks again,
Jeff
Mike in Rancho
Posts: 666
Joined: Sun Jun 20, 2021 10:05 pm
Location: Alta Loma, CA

Re: Light Pollution filter setting for Color module

Post by Mike in Rancho »

Ah, I think I see what's happening. :?

My clarification seems to have gone sideways. Maybe I'm not very good at this. :lol:

A confusing terminology issue, I think. The goal here, as I read it earlier, was to use different Wipe strengths on the different stacks, save those, and then recompose it all together using those saved files.

Pre-wiped meaning already wiped. As in the saves. Compose those. Not the originals.

This goes back to George Carlin of course -- it's not a pre-heated oven, it's a heated oven!


Edit: Also, at the risk of even further confusion -- since both of your original stacks are OSC from the get go, you may be able to replace the compose of the color file (legacy RGB, linear) with just a left-option open, in order to do its unique Wipe and then save it out. Unsure if there's any actual difference in the composed data and what Wipe does between the two for this purpose? :?:
jhart
Posts: 27
Joined: Wed Aug 26, 2020 10:08 pm

Re: Light Pollution filter setting for Color module

Post by jhart »

Hi Mike,

I think you may have put me on the right track.
After stacking the two sets of images, one with the L-Pro filter and one with the UV/IR cut filter, and registering them together, I loaded the L-Pro stack with Open → Linear, cropped it, ran Wipe and saved it. I loaded the second stack in Compose, loading it in each of the R, G, and B channels, used the RGB, RGB (Legacy) Luminance,Color parameter, kept it and loaded it as Linear. I cropped it with exact same settings, ran Wipe, and saved it. In Compose again I loaded the wiped L-Pro file in Luminance and the other wiped stack in R, G and B channels, set Luminance, Color to L, RGB, kept and loaded it as Linear. I did a quick run through the modules to get to Color. In Color, I got the no-wipe warning but the image came up in color. This was kind of a quick run on two separate nights of Triangulum data to see what happened in Color, but this initial effort to wipe the Luminance stack separately from the color stack seemed to give a better result than a single wipe for both. Alternatively, using the L-Pro only for Luminance while using the full color stack for color, may have been part of the improvement. Back to my original post, Saturation is way up to get an idea of the colors.

Thanks again,
Jeff
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