Exercise-Sharpening for Print
So far this course has been very interesting. I have had to research and look at topics that I have never had to look at before. This exercise is a case in point. So what is sharpening and why do we do it?
Well after looking at “The Photoshop Elements 8 Book by Yearby and Kloskowski I discovered the following:-
- Most images will need to have some degree of sharpening.
- Sharpening helps images that are not 100% in focus
- Sharpening gets back some of the original crispness that is lost in processing.
- You can sharpen your images in Photoshop.
- And this rather interesting quote from the book “I’ve never met a digital camera or scanned photo that didn’t need a little sharpening.” Is this really the case?
Looking at the on-screen help in Photoshop , Sharpening normally makes use of the “Unsharp Mask”. It contains 3 values:-
- Amount, the strength of the effect.
- Radius, the size, in pixels, of the effect.
- Threshold, the protection of smoother areas, such as sky or skin.
Chosen Image
As I had not done any sharpening before I suspected that I would not be able to tell the difference between the original image and a sharpened one, especially on say skin tone. In view of this I looked closely at the image looking for an area that I hoped would make the results clearer. I saw that her clothing may have enough detail to show me what the difference would be.
Here is my first test sharpening, the amount of sharpening was suggested , by the author, as a general amount for most images.
First Test
I really was impressed with the result of the first test the difference in the jumper fabric and the black lines on the blouse really stand out. It’s not until you put the two images next to each other that you notice the difference.
Again using the suggested settings in the above book I made three copies of the image with different degrees of sharpening.
Suggested for Portrait
Suggested for Portrait
All Purpose
All purpose
Moderate
Moderate
Here are the three images together to assist the viewer.
Portrait-top, All Purpose-middle, Moderate-bottom
You can see from the above poster that there is a significant difference between the three images. The all-purpose image is clearly not up to standard and is over-sharpened in my view. I do not like the moderate image and in this particular case I do think that the portrait image is the best.
After the images had come back from Photobox I checked the screen settings on our iMac , it was set to Adobe RGB 1998.
I then positioned each of the images around the screen and checked each one against the original image (at 100% magnification).
Well after looking at the printed images with the aid of a newly purchased magnifying glass I can make the following observations:-
- The overall result of which degree of sharpening produces the best image is the same for both on-screen and printed images. However I think this may be because of the vast difference between the three images. Would this change if:-
- The resolution of the screen was different.
- The quality of the screen.
- The images were printed on different quality paper.
- The settings used by Photobox to print the images, even though I used their quality control tool to check each of the images reached the minimum standard.
Of particular note is how skin is effected by the sharpening. The first comparison test I did (see first test image above) resulted in a great improvement in the texture /look of the fabrics. However the opposite seems to be true of skin, the pores in the skin become more evident and this, in my view, gives for a rather disappointing result. This is definitely one area where I will have to be careful in the future if I start sharpening portraits. The safeguard is that the on-screen images gives a reasonable indication as to what the printed image will turn out like.
This has been another useful exercise as I have had to explore a topic that I had not looked at before.
