Enlarging Picture

Sabre · Post by **Sabre** » Sat Jun 01, 2002 11:38 am

I'm enlarging a picture with Photoshop, obivously it turns out a bit blurry. Is it possible to make the picture the same quality as the original, or close to it? I have no idea how to use all of the functions in Photoshop, so if anyone can give me some help as too what I should do. Thanks in advance.

Demis · Post by **Demis** » Sat Jun 01, 2002 12:08 pm

If the picture is in a .jpg format there is not much you can do about quality when you resize it. I don't know Photoshop how it works so i'll say some things i know from Paint Shop, is there an option for smart size or bilinear resample when you try to resize? Most of the times this gives the best quality.

Phantom Lord · Post by **Phantom Lord** » Sat Jun 01, 2002 12:14 pm

Well, I'm no photoshop expert (I usually use Paint Shop) but I found the following to be important if you change image sizes:

If you enlarge or reduce pictures in size you should work with whole numbers, enlarge or reduce them exactly by 2, 3, etc. times. Since the pixels are placed in a grid, you get better results this way because the pixels stay in their relative positions. This counts especially for reducing the size. Of course, you can't get a perfect result if you enlarge pictures, because small pictures simply have less information than big ones.

Sabre · Post by **Sabre** » Sun Jun 02, 2002 1:00 am

I'm working with BMP file, there are three options for resample: nearest neighbour, bilinear and bicubic - bicubic seems to give the best quality. So the only way to get a better quality is to edit it manually after resizing? Thanks for the replies.

Demis · Post by **Demis** » Sun Jun 02, 2002 5:40 am

@Sabre, yes that might be, resize it and then try to enhance the picture, again from what i know from paint shop i believe you can add more colours if the picture is not already to maximum colour configuration. Also posterize or sharpen the picture should give some positive results. Hope that helps.

Sabre · Post by **Sabre** » Sun Jun 02, 2002 6:06 am

Thanks, I'll give it a try.

Moleman · Post by **Moleman** » Sun Jun 02, 2002 2:47 pm

You need Shortcut S-Spline 2. You can purchase/download a demo version from www.shortcut.nl.

Here's a short description:

Enlarging digital images is often a problem.
At the moment most programs use ‘Bicubic’ interpolation, which, as with all common enlarging techniques, simply interpolates between existing pixels to create new pixels. A process like that doesn't "look" whether an image is sharp or smooth, and therefore there's no guarantee that the newly created pixels fit in with the original picture.

S-Spline on the other hand "looks" at the image in an intelligent way, and tries to adapt its patented interpolation method from pixel to pixel, depending on how sharp or smooth the image is in that area. For smooth areas, the algorithm will perform much like B-Spline or Bicubic interpolation. For sharp areas it uses different interpolation techniques and some mathematical tricks, trying to maintain the original sharpness of the image.

It can't do miracles, but it is much better than Photoshop's bicubic interpolation -- an example here.

Sabre · Post by **Sabre** » Mon Jun 03, 2002 12:35 am

Thanks.