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After many issues with image processing on two different monitors and obtaining quite different results from each I decided to buy a gadget which enables the monitors to be calibrated. The one I got is the Spyder5Pro:

IMG_0992_zpsru9zuowh.jpg

It seemed straightforward to run through the calibration routine but the result looks.. a bit odd. That may be because I'm used to a more soft/yellow display and the device tries to calibrate to 6500k (which looks harsh/blue to my eyes). Whatever, I have received comments before that my images have a blue cast so this may explain why - if I'm visually trying to compensate for yellow screen by boosting the blue end of the spectrum.

I've changed the colour balance of a recent image so it looks 'natural' to my eyes with the new monitor calibration, that involved boosting the red end a little, I'm just wondering if anyone has a preference for which appears more 'correct' to themselves. I realise many will be viewing on uncalibrated monitors...

Old colour balance:

M31%20ROF_zpsuqerpfps.jpg

New:

M31%20ROF_zpsqfkxizut.jpg

ChrisH

 

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I recently bought an iDisplay Pro for the very same reason - mostly due to an odd green / yellow cast to my daytime photos.

http://www.xrite.com/categories/calibration-profiling/i1display-pro

I read up before purchase, as you do, and decided to use DisplayCal open source calibration software.

https://displaycal.net/

What I see now is colour profiles loaded for 2 different screens on the same PC, which are remarkably close to each other in terms of colour. I've also done the same for the laptop.

For £200, it was well worth it.

I wouldn't be surprised to see how many people spend thousands on astro imaging equipment, yet have never calibrated their main processing PC.

 

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Second one looks less saturated in reds & blues with a more natural looking "space". But as you say I'm on an un calibrated monitor anyway. I've thought about getting a spyder for years... Well, and/or a really really expensive monitor! I bet its the same for many & always been bottom of the spend list as my thinking has been prioritise catching the best data you can get. But you are right, once you have the data you need to not waste it!

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4 minutes ago, Jonk said:

I recently bought an iDisplay Pro for the very same reason - mostly due to an odd green / yellow cast to my daytime photos.

http://www.xrite.com/categories/calibration-profiling/i1display-pro

I read up before purchase, as you do, and decided to use DisplayCal open source calibration software.

https://displaycal.net/

What I see now is colour profiles loaded for 2 different screens on the same PC, which are remarkably close to each other in terms of colour. I've also done the same for the laptop.

For £200, it was well worth it.

I wouldn't be surprised to see how many people spend thousands on astro imaging equipment, yet have never calibrated their main processing PC.

 

Thanks for that, yes I found many options for selecting a calibration tool - and most have very mixed reviews (this one included). The test will be when I open up the Obs and run the calibration on the 4k monitor in there because results I get from that used to be very different from the monitor on the house PC. I'll never see the two monitors sat next to each other but the results can sit side-by-side so that will be interesting.

ChrisH

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Interesting post Chris, I have looked at this in the past and always been put off by the expense for what seemed to be variable results from other peep's experience.

I have still got a really nice expensive at the time CRT monitor calibrated, but only with grey / colour cards, that I sometimes preview my images on if I'm going to print them and they look completely different to any of my laptops which also produce different colours.

Do the online sites where you upload full res images produce any better colour representations than PNG images uploaded here ?

Never bothered with uploading anything myself as not really my thing.

Sounds like another of those things one could easily get OCD about instead of concentrating on imaging :grin:

Dave

PS Have you tried posting on 10Micron forum lately ?

Been trying for 2 days and failing although it says mine is the latest post it doesn't appear

 

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Dave, different software will produce colours in digital images differently i.e. a web browser will display different to Photoshop for example. Photoshop has colour profiles that need to be understood to be used correctly.

When exporting images from Lightroom for example, srgb colour space should be used for web browsing, whereas prophoto colour space should be used for sending digital images to a publisher for example.

Colour space is important, and likely not used by everyone.

Everyone's image exports, whether tiff, png, jpg or other, will display differently on multiple devices via different software.

Calibration of the processing device (ie PC) is important to get it as close to 'correct' as possible when creating the image.

When I did my displays, editing daytime photos became instantly easier, especially in the shadows and highlights areas of the histogram.

This should hold true for astro images too.

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I have the Spyder 5 and it transformed my laptop into a proper image processing machine but it is equally important that the camera and software colour space are correct..

Alan  

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On ‎08‎/‎10‎/‎2016 at 11:55, Jonk said:

When exporting images from Lightroom for example, srgb colour space should be used for web browsing, whereas prophoto colour space should be used for sending digital images to a publisher for example.

Colour space is important, and likely not used by everyone.

 

CMYK is the usual preference for magazines that go to print. Or at least it was a couple of years ago...

Anyway, I've always calibrated my monitor from my photography days and as said, not all software reads the same scale. The simple way to do it is to use an 18% grey card but that is pretty difficult and useless for astro photos. The other way is to optimise it for print: calibrate your monitor and get a print calibration profile (some companies offer them for free when you buy their paper or ink). Print your image out on your now calibrated monitor and printer, then make any adjustments until it looks right in print. Make a note of your adjustments and always use these (other than brightness adjustments if they are going to be displayed on the web). This way, it's reasonably accurate but more importantly, consistent.

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I noticed that AN asks for submitted photo's to be either Tif or JPEG at high resolution, what does that mean 72dpi ?

Some reproduced images don't reproduce very well.

Dave

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Hi Dave

If you had a 12Mb camera 4k x 3k, and made a 6" x 4" print, that would be 667dpi, rather oversampled as 200dpi is considered adequate for that size of print.

So 72dp would be only good enough for a thumbprint.

I'd just submit at the best resolution you have.

Michael

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8 minutes ago, michael8554 said:

Hi Dave

If you had a 12Mb camera 4k x 3k, and made a 6" x 4" print, that would be 667dpi, rather oversampled as 200dpi is considered adequate for that size of print.

So 72dp would be only good enough for a thumbprint.

I'd just submit at the best resolution you have.

Michael

I have a PGBfly mono camera that produces Tif files 1200 X 700 pixels at 72dpi, I can upscale these in P'Shop to higher resolution but is there any point ?

Turns  5mb file into a 40mb file.

Dave

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Dave, think we're going off-topic here, but suffice to say the splendid images in this post are 1950 x 1800, so why not post your 1200 x 700 images and see how they look?

Also, a 200% upscale shouldn't introduce too many aretefacts, after all what you see here on SGL is often a compromise.

Michael

 

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1 minute ago, michael8554 said:

Dave, think we're going off-topic here, but suffice to say the splendid images in this post are 1950 x 1800, so why not post your 1200 x 700 images and see how they look?

Also, a 200% upscale shouldn't introduce too many aretefacts, after all what you see here on SGL is often a compromise.

Michael

 

Apologies to Chris for the thread drift :)

Vaguely related and I was idly wondering how astro magazines expected images to be delivered to them for printing, they just say "high resolution" ?

I post my images in the solar forum converted to PNG and they look OK, never take much notice of what resolution they end up at.

Dave

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