DSS - where has the colour gone?

[hi8ane]

Just started using the AltairAstro 290C camera on the Dumbell and Ring nebulae to get started on some easy targets. Scope is a 72mm F6 guided. Image capture is Sharpcap which recognises the RGGB bayer pattern.

When I use DeepSkyStacker everything runs smoothly and I get a very nice stacked image but no colour. So to test that the colour signal is getting through I imaged a red light and got a series of images with parallel red and white lines, very visible in the individual frames and unchanged if run through PIPP or Avistack. But DSS gives me a set of parallel black and white lines. The histogram displays colour counts but the output tiff file remains resolutely monochrome.

I must be missing something, a checkbox or process step but don't know what. Can anyone help please?

[PeterCPC]

When DSS has stacked the lights you have to adjust the levels. luminance ans saturation. See capture below. Set the saturation to about 16% and see if the colour comes back. Don't forget to tick apply.

Peter

[hi8ane]

Aha - I couldn't see the Apply button on my screen as I had set the system text size to 125% so the bottom of the box wasn't visible. I couldn't work out why these sliders did nothing!

Will have a play later.

Thanks!

[newbie alert]

There's lots of info around to suggest if you don't align the stack in dss and just use the auto save in the processing software you get better results..

Personally I wouldn't touch the saturation in dss..

[hi8ane]

Appreciate the help but I must be missing something very obvious as DSS is stripping the colour from my images and external processing won't get it back.

As an example here are some screenshots:-

1) a png of a bright red light debayered which is exactly how it appears when opened in DSS

2) the same image after being saved by DSS as a tiff file with no processing

3) the same saved tiff reopened in DSS

As an observation, the histogram on loading changes dramatically if I press Reset. 

Must be missing something  ...

[spillage]

are you using the latest version of dss?

[hi8ane]

4 minutes ago, spillage said:

are you using the latest version of dss?

I'm using 3.3.2 downloaded last week - running on Win7.

The rest of the functionality seems to work well - see Dumbell image above although the Autosave version viewed in DSS is compressed horizontally and shows lots of artefacts to the right. The image opened outside of DSS looks fine (but without colour).

[spillage]

Might be worth posting the file saved from dss here. I would also not make any processing adjustments within dss, just stack and save.

[PeterCPC]

Download 3.3.4 from here http://deepskystacker.free.fr/english/download.htm

Peter

[martin_h]

Have you got the correct debayer settings for your camera?

[hi8ane]

5 hours ago, martin_h said:

Have you got the correct debayer settings for your camera?

I believe so as Sharpcap and PIPP both selected RGGB. As another test I have processed a nicely coloured image of Albireo using Avistack.

 

[hi8ane]

I'm beginning to think that my exposures of M27 were not long enough to capture colour information. I've downloaded Nebulosity 4 and have run the images through and still get monochrome. When I use the Pixel Count tool I get virtually identical counts across R, G and B across the image. Tried the same with Ring Nebula and get the same result.

So I'll stop asking questions (!) and take some longer exposures and try again.

Thanks for the advice.

[hi8ane]

Have now repeated the capture of M57 and M27 with longer exposures (20x30s, gain 100) but still no colour in DSS. Even the RGB sliders are now showing only the greyscale slider.

So I downloaded the demo of Nebulosity and bingo, the colours are there. I like the tools in Nebulosity so will pay for the licenced version. Image quality isn't great (my first ever colour DSO) but at least there's something to work on 

[Atreta]

On 11/14/2017 at 10:32, hi8ane said:

Appreciate the help but I must be missing something very obvious as DSS is stripping the colour from my images and external processing won't get it back.

As an example here are some screenshots:-

1) a png of a bright red light debayered which is exactly how it appears when opened in DSS

2) the same image after being saved by DSS as a tiff file with no processing

3) the same saved tiff reopened in DSS

As an observation, the histogram on loading changes dramatically if I press Reset. 

Must be missing something  ...

Were you saving with modifications applied or embedded? I have a hard time processing if i save embedded in the image, so i prefer to apply and then do the rest of the processing in another software. 

Edit: remember to move the saturation slider before saving it. I slide it to about 20%.

Hth. 

[spillage]

Do not bother making any adjustments in DSS leave this to another program, startools, PI or Ps as they are much better. I am sure it must be a setting in dss that is causing this.

[LightBucket]

11 minutes ago, Atreta said:

Were you saving with modifications applied or embedded? I have a hard time processing if i save embedded in the image, so i prefer to apply and then do the rest of the processing in another software. 

Edit: remember to move the saturation slider before saving it. I slide it to about 20%.

Hth. 

No you have it wrong way round, it is very important after the stacking, you must tick the box that says “embed changes but do not apply” then move to PS or similar for the rest of the processing, if you apply the changes, it will clip the colour and data and you will have nothing to work with..and the images will look almost greyscale..

[Atreta]

Well, here  is what i was talking about:

Just redid it to see if i was mistaken.

this one is with the adjustments applied(saturation to 23% and aligning the rgb sliders and no more processing)

the one below is the same stack although with the adjustments embedded:

[LightBucket]

10 hours ago, Atreta said:

Well, here  is what i was talking about:

Just redid it to see if i was mistaken.

this one is with the adjustments applied(saturation to 23% and aligning the rgb sliders and no more processing)

the one below is the same stack although with the adjustments embedded:

Yes that is correct the bottom one is a normal stack from DSS and is what all mine look like after just embedding changes but not applying, BUT as soon as you get to PS and give it a go with levels and curves it will all appear before your eyes, so to speak, the other one you show above, because the changes would have been applied, will be as good as it gets, as the data will have been clipped and probably only around 60% of the data left....yes it looks better there, but it is not...trust me and try it out, send them both to PS and runs through levels and curves and see what I mean...as soon as you apply the changes it will freeze the data at what it is, and you wont be able to manipulate hardly anymore...

[Atreta]

Cool, gonna give it a try again. 

 

[alan potts]

I am far from expert having only started the other week, I did about 20x30sec with my 40D Canon on 1600iso, did all the lights and so on. End result looked B&W and you couldn't really see M27 at all, until I put it in Photoshop and changed it to an 8 bit image for Jpeg. I was well pleased for my first effort.

 

 

 

 

Alan

[LightBucket]

1 hour ago, alan potts said:

I am far from expert having only started the other week, I did about 20x30sec with my 40D Canon on 1600iso, did all the lights and so on. End result looked B&W and you couldn't really see M27 at all, until I put it in Photoshop and changed it to an 8 bit image for Jpeg. I was well pleased for my first effort.

 

 

 

 

Alan

Good first effort

You shouldn’t change to 8 bit, until you have gotten as much out of it as possible, as that will also clip the data and you wont really be able to edit it again..

[alan potts]

2 minutes ago, LightBucket said:

Good first effort

You shouldn’t change to 8 bit, until you have gotten as much out of it as possible, as that will also clip the data and you wont really be able to edit it again..

I did make other copies that I didn't change that came from DSS so I can add to it, at least that's what the plan is. I am only playing at the moment as you can tell by the black sky, as if. Thanks for the advice.

Alan