Resize photo or line art without loosing quality - How? 2

[5t6y7u8i]

We have tried to reduce or enlarge line drawings and photos and ended up with a degraded picture. Mabey a 5 x 7 inch to a 8 x 10 or something like that. Not a huge change. Sometimes a smaller change in size. Files are jpg. Looked for a past message, didn't see one. If one is on this list let me know. Thanks.
P.S. I know think this is fairly simple, I hope.

 

[HowardMarks]

Hi,

Generally speaking, whenever you increase an image's size you will end up with some degradation, simply because the computer has to 'guess' where the extra pixels are coming from. Your images tend to look more blurred to compensate.

There are programs which claim to use fractals to intelligently enlarge an image whilst maintaining quality (such as Altamira Fractals plugin for photoshop at

http://www.altamira-group.com/).

The best advice would be where possible to start with a very high resolution image and reduce it in size as you need.

If you say you are losing quality when reducing what kind of degradation are you finding? Check that the image mode is set to RGB or CMYK and not Indexed Colour or Duotone.

Finally, if you are enlarging or reducing the images so that you can print them larger or smaller, try just setting the document (print) size rather than actually increasing or reducing the pixel size, and see if this helps.

I hope this is of some use Nick (Web Designer)

http://www.retrographics.co.uk

nick@retrographics.co.uk

 

[Manic]

I would go with that Idea. Photoshop handels image resize in CMYK and RGB a lot better that in the other formats.

A little trick that sometimes works is the en;arge or reduce the image in small steps, as I say this doesn't always work.

Manic
-----------------------------
I've broken it again !!
-----------------------------
lee.gale@virgin.net

 

[eamc]

As you resize an image in the IMAGE SIZE panel of PS, look first at the information in megabytes (Mb) that the starting image contains. You can now enter both a new size and a new lpi or ppi resolution, and as you do this, the Mb will change, but there is no use going ABOVE the original figure - keep your resolution reasonable. Thinking in Mb, I have never encountered visible "degradation." Degradation is more likely to come from your opening and resaving a .jpg image, especially if you use drastic compression (low quality). Try saving the original image as .psd instead of .jpg and see whether it still degrades on resizing. Photoshop .psd is a lossless open-change-save-open-change-save operation.

Edwin

 

[jackal63]

another point is that when enlarging a picture, try not to alter the original 1:1 picture ratio thus causing deformation. E.g if you start with a picture that is 200 x 150 and you want a picture that is say 400 X 270. Maintain the aspect ratio and enlarge the pic to 400 X 300, then CROP the width down to the desired 270. That might help maintain picture quality.