UTKARSH MISHRA ASTRophotography
Making RGB Image in Photoshop CC
Processing images can be a tricky job especially if you are completely new to this hobby. I see many people asking about how do we make a color image from a Mono-camera
1) Open your RGB tiff files in Photoshop, make sure that they are in 16bit tiff mode as PS only supports 16bit images, if you do not know how to convert32bit into 16bit here is the procedure-- Go to>Image>mode and change it to 16bit, a dialogue box would appear change the option to highlights and compression press enter.
2)Now its time to Stretch your image. Go to>Image>Adjustments>Levels or Simply Ctrl+L then a Histogram would appear , you can use Levels and curves both for stretching images but levels is more convenient as its easy and straight forward to use
3)Now on your screen you would see 3 triangles, triangle to the left is known as Black Point , Middle one is known as gray point and triangle at the extreme right is known as white point, we only use the black and gray point.
4)Now using your mouse slide the grey point to the left and press OK, while making this adjustments you would notice the change in image.
5)Now repeat the same by opening levels again, now you will notice the change in histogram it has changed, now use the black point and slide to the right just before where the histogram starts, please be very careful while stretching image sometimes you can overstretch or clip in the image data, it is advised to keep the black and gray points just at the right place like i have shown in image. keep repeating the steps until you data is pulled out nicely yes be advised not to overstretch an image which barely has a good amount of integration time
6)Stretch the Red ,Green, Blue Tiff files as shown above, After Stretching individual files now its time for combining them in Photoshop CC ,its an easy task first copy the Red file using Ctrl+A and Go to option Edit and copy , or do CTRL+A>CTRL+C. Now the Image properties have been copied to your clipboard
7)Now go to New a dialogue box would pop up change the color mode to RGB and background contents to white. Press Ok and untitled image will appear
8) Now copy the Red and go to the channels and paste using CTRL+V, repeat the same thing to Green and Blue , after you have pasted all images to their respective channels click on the eye icon at RGB as shown
9)Now you Basic RGB image is completed, ofcourse it needs lot more image processing since this was a very basic tutorial for beginners and I wont be going deep in this but yes in next article I would write about adding Luminance to your image. i hope you liked this tutorial sorry for my bad grammar still learning LOL and here is the final image i processed from this data
Data Credits : www.inisghtobservatory.com