Is there any drop in quality if I 'downsample' image?

Veronica Choo · 19th April 2004

In PS, suppose my image starts off with enough pixels for 8 x 12 at 360 ppi. But I want to print at 4 x 6, 200ppi and don't want the extra space on the CD. So I need to resample the image. I know that upsampling will degrade the image. But what about this case of 'downsampling', that is throwing away unneeded pixels?

Thanks!

Sion · 19th April 2004

I guess it would affect image quality marginally if dowmsampling to half size. I wouldn't downsample 360ppi to 200ppi unless that's the resolution optimum to the output device.

Another thing to consider is that some subjects e.g. images with soft tone are easier to downsample than images with lots of details and sharp definitions.

Why not run a print-out of an important section of the two images side by side and see for yourself whether the dowmsampling quality is acceptable to you?

CDs are so cheap these days that downsampling images to fit images into a CD is something you very rarely need to think about.

coke21 · 19th April 2004

Originally Posted by Veronica Choo

In PS, suppose my image starts off with enough pixels for 8 x 12 at 360 ppi. But I want to print at 4 x 6, 200ppi and don't want the extra space on the CD. So I need to resample the image. I know that upsampling will degrade the image. But what about this case of 'downsampling', that is throwing away unneeded pixels?

Thanks!

Most printers (FDI) can print up to 300dpi. So why not keep it at 300dpi instead? Also, images of 200dpi are of acceptable quality so don't think its a problem if you do downsize it to 4x6 200dpi.

Veronica Choo · 20th April 2004

Hi Sion and Coke...Thanks.

I've just received my prints back. They looked all right even though I had downsampled from 360 to 250. But just a few prints don't look sharp even though they looked very good on my screen... So I'm wondering if downsizing would affect. Anyway, the next time I print, I guess I will stick to the original 360ppi.

I just thought it's an overkill even though I use CD storage.

sehsuan · 20th April 2004

aiyah, use CDRW lor. after get back can format and reuse...

use the highest DPI you can, if you can have more pixels to describe the pic, why do with less?

19th April 2004	#1
Veronica Choo New Member Join Date: Feb 2004 Location: North Posts: 17	Is there any drop in quality if I 'downsample' image? In PS, suppose my image starts off with enough pixels for 8 x 12 at 360 ppi. But I want to print at 4 x 6, 200ppi and don't want the extra space on the CD. So I need to resample the image. I know that upsampling will degrade the image. But what about this case of 'downsampling', that is throwing away unneeded pixels? Thanks!

19th April 2004	#2
Sion Senior Member Join Date: Jan 2004 Location: 新天地 Posts: 1,012	The answer is Yes and No I guess it would affect image quality marginally if dowmsampling to half size. I wouldn't downsample 360ppi to 200ppi unless that's the resolution optimum to the output device. Another thing to consider is that some subjects e.g. images with soft tone are easier to downsample than images with lots of details and sharp definitions. Why not run a print-out of an important section of the two images side by side and see for yourself whether the dowmsampling quality is acceptable to you? CDs are so cheap these days that downsampling images to fit images into a CD is something you very rarely need to think about. __________________ 三分天注定, 七分靠打拼, 爱拼才会赢!

20th April 2004	#4
Veronica Choo New Member Join Date: Feb 2004 Location: North Posts: 17	Hi Sion and Coke...Thanks. I've just received my prints back. They looked all right even though I had downsampled from 360 to 250. But just a few prints don't look sharp even though they looked very good on my screen... So I'm wondering if downsizing would affect. Anyway, the next time I print, I guess I will stick to the original 360ppi. I just thought it's an overkill even though I use CD storage.

20th April 2004	#5
sehsuan Deregistered Join Date: Dec 2002 Location: Singapore Posts: 6,674	aiyah, use CDRW lor. after get back can format and reuse... use the highest DPI you can, if you can have more pixels to describe the pic, why do with less?