Author Topic: Jpeg image  (Read 2039 times)

Offline tgervais

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Jpeg image
« on: 2017 February 04 17:17:04 »

I want to save an image I am working on which is a color image,  and I want to save it as a jpeg file.
I saved it as a jpeg only to end up with a black and white image very low in contrast .  It needs to be worked on to get it to be like my color image.

Is there a simple file that can make this into a color Jpeg image?   And an image that won't need any more work?

Online Geoff

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Re: Jpeg image
« Reply #1 on: 2017 February 04 17:28:00 »
The only reason I can think of that will cause this is that your colour image has a screen stretch applied to it
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Offline tgervais

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Re: Jpeg image
« Reply #2 on: 2017 February 05 11:12:32 »
The image I am trying to save as a jpeg has had the full treatment of all the processes of pixInsight.
It has been stretched, it has had pixmath applied along with starmask, and multiscalemediantrasform, Rangeselection, HDRmultisaletransform, and exponential transformation.

Now - I need to save it as a jpeg and not a tiff or something else.

How can I do that with the saved image coming out in color or being the exact same image that I am lookiong at when in pixinsight??

Online Geoff

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Re: Jpeg image
« Reply #3 on: 2017 February 05 11:41:45 »
I think you will need to post your image so people can inspect it. I save files as jpegs often and have never had the problem you describe.
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Offline tgervais

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Re: Jpeg image
« Reply #4 on: 2017 February 05 13:39:41 »
Thanks Geoff.  Your patience is appreciated.

I am just a newbie with pixinsight but trying to learn.  The saving of a file as a jpeg has something to do with it being linear or not.  I think. 
Not sure but I seem to think I read that in one of the tutorials.   If you are working with an image in linear mode than you can't expect to save that as you would a non-linear image.   Something like that.    And of course my images are all linear and when I take it out of linear mode I have no image left. 

If I want to view the image in non-linear mode  I have to run it through all the same processes that I put the linear image through.  And this is what I am trying to get around.

In other words,  when I get finished playingi with an image (in linear mode)  and I now want to save it as a jpeg - I can't .  I end up with nothing.  Or rather I end up with a non-linear mode which is nothing.

Perhaps some of this explanation might help you understand where I am at.   I just need to know that after you are finished polishing up an image ,  how do you save it as  a jpeg..??

Online Geoff

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Re: Jpeg image
« Reply #5 on: 2017 February 05 14:34:58 »
Make sure the image is nonlinear, then go to File > Save As, the select jpeg from the pull down menu in the window that appears.  If this doesn't work, then you really have to post your image.
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Offline tgervais

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Re: Jpeg image
« Reply #6 on: 2017 February 05 14:55:45 »
Geoff..
Thanks again.

Tell me - how do you make the image non-linear?   I mean,  after it has been worked on and dressed up and made beutiful in linear mode,  how do you convert that to non-linear and not lose all your work??

I know how to save a non-linear to jpeg.  That is not my problem.  I want to save a beautiful linear image to jpeg without having to go through non-linear mode?? 

Does that make any sense.??


Online Geoff

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Re: Jpeg image
« Reply #7 on: 2017 February 05 15:14:58 »
Please indicate what steps you have gone through to arrive at your final image. And you MUST post the picture.  This is all just guesswork until I have something definite to go on.
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Offline Carlos Milovic

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Re: Jpeg image
« Reply #8 on: 2017 February 06 06:05:43 »
Disable the STF. If it shows a black image, it is still linear. You have to apply histogram transform (or anything equivalent) to stretch it. STF is only for display. It does not change the pixel's values.
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Offline tgervais

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Re: Jpeg image
« Reply #9 on: 2017 February 06 07:07:05 »
OK.  I have disabled STF and I get a blank/black image.  So I used HistogramTransformation and curves etc to get some sort of a picture.  Not as good as it was when it was a linear image.  Here is the Jpeg now.  Finallyy I have a jpeg that is not black..

Offline eganz

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Re: Jpeg image
« Reply #10 on: 2017 February 06 12:45:31 »
if you want to keep the look of your Linear image, then you can look up how to apply the STF.
This can be a process where you drag from the STF box the Icon onto the histogram box and then apply it to the image.
Alternatively, you can download and install the script called "apply STF". This will solve your problem.
however, in general it is recommended that you stretch your images using the appropriate stretching tools.

Offline tgervais

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Re: Jpeg image
« Reply #11 on: 2017 February 09 15:57:23 »
You are right on with your thoughts on moving the linear image over to non-linear.
Worked like a charm when I  dragged  the STF box from the Icon onto the histogram box and then applied it to the image..

I guess I knew that I could do that,  but somehow it didn't jump up and bite me..

Thanks for your help guys..