Discover Image Size & Resolution for Photoshop CS

The easiest way to make a copy of an entire .psd file (or any file) instead of doing the old school method of select: copy: paste and then maybe dragging in layers (which believe it or not I used to do), you can just go to Image: Duplicate.

Here you can enter a new name if you want. Press OK and you have an exact duplicate no matter the file size.

Here is the duplicate..

Remember that you can highlight only a portion of the text and make alterations to it such as changing it to a different color.

If you right click on the top of the document window you have some options to choose from. You can duplicate the document right from here or go straight to the image or canvas size, etc.

Bring up the Image size dialog box (also under Image: Image size). Now change the dimensions.

Try entering an amount that’s half of what is there. When you have constrain proportions on, it will scale the image down automatically to the proportionate value so you only need to change one of the entry boxes.

Here I’ve gone from 800 to 400 @ 90 dpi (the original resolution). You’ll notice that obviously the image is smaller and half the size that it used to be.

Now that you have a duplicate you can Save to overwrite the latest version of it. Because you already named it, you had created a new blank file. Be sure to save files where you want them before you close them out. If you haven’t saved a file, Photoshop CS will ask you if you want to save them. If you want to retain the original state of the image then don’t save it (in this case that would be a blank document).

Under the image size dialog box you can make some more changes.

Change the resolution to 72 which is screen resolution (size) for computers and the world wide web. 72 is the number of dots per inch (vertically and horizontally). You don’t need to have more than that for the WWW viewing or emailing pictures.

With a lower resolution, the file will save more space and will also scale the dimensions down because there are fewer pixels per square inch. More resolution (a higher dpi) means that there are more pixels crammed into an inch. This translates to better image quality for enlargements and print because there is more image data information. When you try and blow up 72 dpi much larger, pixels can’t just be made up out of thin air so they start appearing blocky.

A higher resolution will allow you to zoom in closer to see what's really in an inch. Resolution is set by your camera or when you scan in pictures. You can’t go higher (in Photoshop) than the resolution ‘captured’ at or you will lose image quality.

Capturing at a higher resolution gives you more options but also takes up much more space in your computer. Mostly you won’t be starting out with billboard prints so if you’re just working for web 72 dpi (most consumer digital cameras) will work nicely for computer purposes. 300 dpi is the standard for print and even higher resolutions if you want to blow up enlargements.

If you’re wondering why your digital 8X 10 prints don’t look the best it could be because your camera is only capturing at 72 resolution.

Double click on the zoom tool to bring the working document to 100%.

Even after you change the resolution you can always change the image dimensions (safest to always go smaller to retain quality with low res).

You can now Save As and choose a different file name to save a copy or you can save in a different file format for a copy or just Save to overwrite the file. I always use .psd and .jpg’s the most often. I’ll save my designs in .psd and export as .jpg’s (which flattens all of your layers). I don’t recommend .bmp. Gif’s are used best for vector format work or if you want to preserve transparency (a whole different topic).

To gain a solid foundation of proficiency in Photoshop CS or CS2 find out more about my TutorialKey Photoshop CS/CS2 Video Tutorials Training and how it can help you reach your full Photoshop aspirations. I go over working with files in depth and cover interpolation, file formats, saving, preparing for web, slicing and ImageReady and much more.