View Full Version : Jpegs look low resolution when enlarged- help!...

02-03-2011, 8:02pm
Hi Guys, I use Photoshop CS5 and shoot in RAW+JPEG, and then edit the raw files and save as Jpeg, highest res (10) but when i enlarge the size of the photos, i.e. set as a background on the laptop, they don't stay clear?

I shoot with a Canon 550D which is an 18 megapixel camera and i dont understand why my images look so grainy when larger than the standard size. I know that when you get things printed, you can up the resolution (i havent had anything printed), but im becomming concerned about supplying what the industry says is 'highest resolution' photos that actually arent. I did read a few articles that say to save your RAW files as .tif instead of jpeg- would that make a difference?

Thanks in advance.

-Imogen (confused and bewildered).

02-03-2011, 8:08pm
what pixel size are they saving as? Have a look at a JPG and come back and tell us how many pixels high and wide they are. My guess is that either you, or your software is resizing them.

02-03-2011, 8:16pm
Is it happening with all settings? Is your ISO high therefore your images may have noise which is causing the grainy look? I know my 450D has poor ISO performance and can really only have it on either ISO100 or 200

02-03-2011, 8:27pm
No, it's not the ISO settings... Thanks Rick, i'll look at that tonight.


04-03-2011, 1:10am
Hey Rick- i looked up the pixels and they are W 4936 x H 3425 resolution 240 dpi. Is that low?

04-03-2011, 7:48am
No that is not low. So the blurriness at larger display size is therefore not related to a reduced image size, so that discounts that as the issue. It could now be one of two things, you are compressing it to much by using to high a setting for your JPG conversion that is pixelating the result, or the original photo was blurry. Post an example here and we may be able to assist

04-03-2011, 1:28pm
Yes, it has to be something i'm doing, conversion wise, as enlarging the RAW file stays perfectly sharp and clear.


This is the photo i tried to set as my desktop background that wasnt sharp when enlarged to a 15" laptop screen. Your help is appreciated guys, i'm totally stumped.

04-03-2011, 2:02pm
Imogen, is it only when resizing for you desktop background that is causing loss of sharpness? I think that sharpness can be lost here because the desktop resizing algorithms are not very sophisticated. Try this: find the resolution of your monitor (for example 1024 x 768) and save a resized jpg with pixel dimensions that match your desktop (you may need to crop to fit). Sharpen the image (eg unsharp mask) after the resize step. Use this image as your desktop and see if is better. (The desktop software now shouldn't need to do any resizing.)


04-03-2011, 2:03pm
This is the photo i tried to set as my desktop background that wasnt sharp when enlarged to a 15" laptop screen. Your help is appreciated guys, i'm totally stumped.

If it is exactly the size as posted here (no EXIF to see) then you could expect some loss of quality. A couple of Qs...

1) Is your laptop screen the same aspect ratio as the image? If the image is stretched more in one direction only then this will help degrade image quality.
2) Have you made the file you want as background the same size as the resolution you have set on the laptop screen?


04-03-2011, 5:03pm
This is all very possible- wont be able to check until i get home though- thanks guys!