Here is a good quick start guide to using Adobe Photoshop 7.0 for enhancing a planetary image. For this example, a recently processed image from Registax 4 was used. See Registax 4 tutorial here.
In this photoshop tutorial, we will introduce some basic tools for cleaning up and enhancing an astro-photo including:
- Rotating Canvas
- Unsharp Mask
- Color Balance
- Hue and Saturation
Resource for Astrophotography Processing in Photoshop- Deep Space Images
For in-depth instruction on processing deep space images in Photoshop CS3, check out Adam Block’s DVD Making Every Pixel Count- Powerful Processing in Photoshop . For planets, refer to the quick start guide below by Astrophotography Tonight!
Quick Start Guide for Adobe Photoshop 7.0 Starts Here
Open Image File in Photoshop
After launching Adobe Photoshop, click on the File menu and select Open. Find your image where you saved it on your computer. Select your file then click the open button.
Crop Your Astro-Image
If your image is not centered, the crop tool will help. Simply click on the crop tool icon in your tool panel and draw a box around your planet with the left mouse button. If you need to resize or adjust the box, simply drag the corners or edges of the box inward or outward to the desired location. When the box frames your planet to your liking, press the Enter button on your keyboard. Now your image is cropped!
If your object is not oriented correctly, you can simply rotate the canvas in Photoshop to fix it. Just click on the Image menu and select the rotation that is desirable such as 180 degress, 90 degrees clockwise, flip canvas horizontal, etc.
Photoshop Levels Tool for Astrophotography
It may be necessary to increase or decrease the contrast of an astro-photo. You may want tweak the contrast levels to cut down on a bright nucleas or increase it to bring out more detail in an image. One way of doing this is to utilize the level tool in Adobe Photoshop. Just click on the Image menu, Adjustments, then select Levels. Try adjusting the Input Levels slider to see the affect it has on the image. Adjust to the desired level. Also note that you can adjust the colors red, green, and blue individually if you need to make further adjustment to the color.
This Photoshop tool is nice for astrophotography when there is too much noise in the image. The noise can originate from over-processing (e.g. with Registax wavelets) or from the camera during the imaging session. In any event, some of the noise can be removed with the despeckle tool. To use despeckle, click on the filter menu, Noise, then click the Despeckle tool. Check for improvement in your astrophoto. If further cleanup is needed, follow the same process again. Be careful not to use despeckle too many times or you will lose fine detail in your image.
This Photoshop tool works much like the wavelets in Registax. It can be thought of as the opposite of the despeckle tool. It can help bring out detail in the astro-image. You must be careful not to over-sharpen the image though because it can become grainy and unnatural looking. To access unsharp mask, click on the filter menu, Sharpen, then Unsharp Mask. Note that as you increase the “Amount” slider, you sharpen the photo.
Color adjustments can be made to bring better balance of color to the object. Levels can be adjusted in the cyan to red range, magenta to green range, and yellow to blue range. Hopefully the color does not need to be changed from the way the camera captured it, but if necessary, here is how. Click on the Image menu, Adjustments, then select Color Balance. Sometimes in astrophotography it is necessary to change the color of an object to enhance certain details. Sometimes detail will stand out in false color and is used for demonstration purposes. An example is to increase the color blue in Jupiter to enhance detail in its cloud belts.
Hue and Saturation
Sometimes your camera may not capture the color in its natural form. Or, you want to present your image in false color for detail enhancements. If this is the case, then try tweaking the hue and saturation in the astro-image. Click on the Image menu, Adjustments, then select Hue/Saturation. Adjust the Hue slider to obtain the desired color. And, adjust the Saturation slider to increase or decrease the hue. Note that you can make adjustments to the individual colors as well.
Photoshop CS3 Astrophotography Instructional DVD
Making Every Pixel Count- Powerful Processing in Photoshop for Astrophotography. Learn to process astro-images in Adobe Photoshop like the experts do! Learn more about this incredible instructional DVD available through AstroPhotography Tonight!
Learn higher level concepts and procedures for processing astro-images such as data rejection techniques, deblooming techniques, star replacements and substitutions, sky and star adjustments, noise reduction, star repair, and much, much more! Adam’s Making Every Pixel Count DVD contains 25 sections of on-screen training adding up to 9 1/2 hours of instruction!