I wrote this article on 8 September 2003.

Suggestion: maybe you should scroll down futher this page to see some before and after images of Mars to convince yourself it is worth it to read the text below:

After many weeks of trying out all sorts of fancy image processing tricks, I realized that my computer's monitor was not calibrated properly. The brightness and contrast were both wrong - it was the way I liked it, but not according to the standard everyone else uses.

This causes many of my website pictures to be too light. I also noticed some of the black backgrounds have diagonal lines on them - evidence that I rotated the image of Mars to get south at the top. With my computer monitor set as it was, I did not see any of this - it looked perfectly black.

So if you see some truly AWFUL images here, that is not my standard of work. It looked OK, up until I calibrated my monitor. I will fix these problems over the next week.

The way my computer screen was set meant that my captured Mars images were of low contrast with dark areas also very dark. This made processing the past 3 months very difficult. With the new settings my processing is MUCH easier - I can see variations in brightness that I previously did not see.

This 'discovery' of mine have several other important implications:

• When I captured some bitmaps / avis of Mars this evening, the newly calibrated monitor made focussing much easier.
• Tonight was cloudy and nearly full moon with Mars very 'close' to the moon. However I noticed that I am now able to take MUCH better images with the new monitor settings.
• I can also do better image processing since more detail and shades of colors are easily visible.
• The pictures of the Hubble telescope now have more detail in them where previously they had 'large' featureless areas.
• I suspect the variety in quality of other astrophotographers images are caused ( partly ) by differences in monitor calibrations. Their images look quite good on their monitors but when uploaded to the Internet we see hopelessly underexposed images with some ugly artifacts visible in them.

  This issue might not be as bad as I think, but this might be what happens ... an astrophotographer upload his/her masterpieces to a commonly shared gallery and think by themselves - wow, my images are nice, look how bad the other peoples' images look. In the meantime everyone else sees this astrophotographer's images as being ugly, and ALL the rest is perfect. So our poor astrophotographer is blissfully unaware of the problem. So you must look at your images using a variety of different computers - as well as a Mac, Intel PC computer and Unix workstation if possible.

So if you come across large galleries of images not looking too healty, it might just be that your monitor or the monitor of the gallery creator is not calibrated. Images on the web look different when created on a Mac and viewed on an 'Intel' PC and vice versa. So if you upload your images to the Internet you MUST ensure your computer screen/monitor is calibrated properly otherwise your images will not look AT ALL they way you think it does.

Relevance of monitor gamma calibration to webcam astrophotographers

Our webcams use its settings to capture images using its black and white points.

Our computer screens are set up to display a certain range of shades of colors - with its black and white points.

Images are displayed on the Internet using another set of these color ranges and shades.

Obviously if these 3 ranges are in conflict, like in my case, you will struggle with image processing. Worst of all, if you only work on one computer, you will never see your images the way other people see it, so you will never realize how ( possibly ) horrendous your images look - even if it looks OK to you.

I typed this webpage quite quickly just to get the word out. Please read up on the matter and calibrate your monitor when you understand what you are doing. I thought monitor calibration was only for graphic artists - I was wrong.

No need to panic, it might be that your monitor is set perfectly and that I am one of the 5 percent of Mars webcam astrophotographer with this problem.

Here are several sets of before and after monitor calibration images:

      

      

First image is before calibration.

Note added - 9 Sept. 2003 - After I calibrated my computer screen correctly I noticed the previous picture I posted here look horrible. Using just brightness changes did not fix it, so I reprocessed it from the origional raw image.

Please let me know that my images inside this box are now looking much better than the ones above - outside the box.

I do not want to make another mistake by fixing my images after monitor calibration and making it even worse.

Please say in your email whether you used an uncalibrated monitor or not.

Thank you - my address . . . alwynbotha - - - at - - - webcam-astrophotography.com

If you can clearly see the massive difference monitor calibration makes, please let your friends know of this webpage. Thank you.