| » Forum Index » Image doctor » Topic: Image Resolution |
|
Posted on 29/11/10 5:40:56 PM |
|
Faith Ince
* Posts: 28 Reply |
Image Resolution
I use Photoshop and often have to change the resolution for printing, etc. Images open at 240 Resolution, and I change them to 300. I save them as such, but when I open them again, they show as 240. So unless I print straight after changing to 300, before closing, I cannot seem to be able to print at 300. Any advice? Faith |
Posted on 29/11/10 11:35:07 PM |
|
Jota120
Ingenious Inventor Posts: 2615 Reply  |
Re: Image Resolution
Small help: I've never had that problem. If I change resolution 240 to 300 and save afterwards as a new PSD file name: When reopen new file it opens again as 300 in the new file. ......... another issue printing, PS -> drivers for your printer! and stuff, does my head in  , but more to do with colour space, not 240 vs 300 image issue you raise.
|
Posted on 30/11/10 2:16:46 PM |
|
Nick Curtain
Model Master Posts: 1768 Reply  |
Re: Image Resolution
Hi Faith Experts and Print Labs will always recommend that 300ppi is the standard resolution to use however, unless you are printing very large, my view is that you are unlikely to tell the difference between 240 and 300, so I wouldn't worry too much, unless the lab insists on a certain size. Digital cameras from different brands are very inconsistent in the file size they produce. Some will produce 72, whereas others will produce 180 and others 240 and there may be other variables. What really matters is the size of the file and how large you want the print. Resolution is a huge subject, so to grasp the basics it's a good idea to experiment with the resize dialogue and see what happens. If you open a file at 6X4 inches @ 240ppi and resize it to 300ppi, you will see the dimensions of the image will change to 4.8 in X 3.2in. So what PS has done is to retain the same number of pixels, but squash them into a smaller space. If you were to do the same with an image at 72 ppi, the dimensions would become 1.44 X 0.96in, so not very useful at all. This is where resizing an image comes into play, through a process called interpolation, which PS and other dedicated software does very well. In short it re samples the image and invents information. You can do this via the dialogue box, but more importantly via the crop tool. If you look in the toolbar there is provision to crop at a resolution. You will see that in the example the crop is 8 X 12 inches @ 300 ppi. When you drag the crop the image will take on these dimensions. The beauty of this is that you can perform the crop and resizing at the same time, which avoids a two step process and image degradation. With the crop you can straighten verticals and horizontals and even perform a perspective crop if you wish. There are different methods of interpolation and you'll see the options in the dialogue dropdown. I would stick with Bicubic Smoother and sharpen the image for the desired output. I believe the crop will follow the interpolation method you have selected as default within the image size box. I hope you find this useful and time saving. Nick  |
Posted on 05/12/10 10:55:13 AM |
|
Thistle F. Ince
* Posts: 23 Reply |
Re: Image Resolution
Many thanks for all your help. I will have a go and try all the solutions posted. Faith |