Teach Yourself Photoshop 4 in 14 Days

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Optimizing Memory Preferences

Photoshop requires a lot of memory. By memory, I mean both RAM and hard disk space. The hard disk space is required for storing large files, and at least 10 megabytes of RAM are required to run the application. Then, add to this 10 megabytes the size of whatever files with which you happen to be working. Say you are working with a 2 megabyte TIFF, well, then, you will need at least 12 megabytes of RAM. Otherwise, Photoshop will use your hard drive as virtual memory, which is extremely slow.

The bottom line is, get as much memory as you can afford. I recommend not less than a gigabyte of hard disk space and at least 24 megabytes of RAM.

Basic Photoshop Preferences

Preferences are settings that you choose according to your own preference that control how the application operates.

After you set them, the Photoshop remembers even after you close the program. These settings then become permanent unless you decide to reset them. Sometimes you will find that Photoshop will begin to do strange and unusual things, confounding your best attempts to solve the problem. You might want to try trashing your Preferences file (found in the System folder on Macs and in the Prefs folder in the Photoshop folder for Windows users). Throw it away and restart Photoshop. The application will automatically rebuild a preference file for you. It's sort of like starting all over again, but it can sometimes solve problems that other fixes can't.

General Memory Preferences

There are two types of memory in the world of computers. There is hard disk memory and there is RAM. Both have an enormous impact on the performance of Photoshop. The concepts aren't easy to grasp. Even seasoned professionals will admit that they aren't sure what the difference is. But when you do you will have a greater understanding of Photoshop--how it works as well as how your machine works.

The hard disk is where you save images. It is measured in megabytes (MB). If you are using a newer machine, you probably have somewhere around 500 megabytes of hard disk memory. It is where your system and your applications are, so to speak, recorded so that you can open them and run them. This is where they reside. Think of it the same way an old vinyl record contains songs. They are physically inscribed on the vinyl as grooves, which the needle then interprets as sound.

RAM, however, is a little different and, generally speaking, a lot more important. It too is measure in megabytes, but this number is much lower than the number for the hard disk. Most systems (Macintosh or Windows) ship with 8 or 16 MB. 16 MB is enough to run Photoshop, but to really accomplish anything you are going to need 24+.


NOTE: As a rule of thumb, get the most RAM you can. 24 megabytes is adequate. 32 is pretty good. The more the better. RAM is, at the moment, fairly inexpensive. Buy as much as you can afford.
Make sure, however, that you consult your hardware documentation for the proper type of RAM for your system.

This is where an application exists while it is open and running. When an application is not open it is just sitting on your hard disk taking up physical space. When you open it, however, it exists in what you might call virtual space. RAM chips are not physical memory. They are electronic memory.

This means that they are extremely fast (operating at the speed of light), but they are volatile, meaning that if you quit Photoshop without choosing Save from the File menu, all of your work will be lost.


NOTE: Always save your work--File+Save or File+Save As. The former command saves whatever changes you have made over the original document you opened. If you want to save changes, but want to keep the original file intact, choose the Save As command.
See later in this appendix for more information on saving files.

To put this in more concrete terms, consider a system, be it Macintosh or Windows, with 16 megabytes of RAM. Say, for instance, that the system (Windows 95 or the MacOS) takes up roughly 3-4 megabytes of RAM. (Remember, these are running applications too.) Photoshop itself takes up somewhere around 10 megabytes. This leaves you about 3-4 megabytes of space in RAM.

Take my word for it--this is not a lot. Photoshop files easily can grow to 10 or 20 megabytes--and then some.

You need enough RAM for Photoshop to itself be open and then have room to open big image files.

Memory for Macintosh Users

For Macintosh Users Only: Click once on the icon for Photoshop. Then, select File+Get Info (Command-I). At the bottom of this dialog box, you will notice the preferred size for the application. This refers to the amount of RAM allocated to the program. Make sure that you use at least the minimum, but don't let the maximum number be a ceiling. Allocate as much RAM as you can, even if it means that you can't open other applications. The performance increase in Photoshop is worth it.

Memory for Windows Users

If you happen to be using a Windows machine, you also can set how much memory Photoshop uses. Go to File+Preferences+Memory & Image Cache

Here you can set how much memory you want to allocate to Photoshop. If you are going to be using Photoshop by itself, then go ahead, allocate away. If, however, you are like most people, and will be running other programs simultaneously, you might want to keep this at the default. Feel free, though, to change it when you need to work with an especially large file.

Troubleshooting Memory Problems

For Macintosh Users Only: If you are having trouble with Photoshop--the program can't open files, or even it refuses to open, you can drag your Photoshop Preferences file (which is found in the general Preferences file within your System folder) to the Trash.

After you have done this, try opening the Photoshop application again. As it opens, it will create a new, albeit default, Preferences file. You will then have to reset your Preferences the way you like them, but this is a good way to get a fresh start, and can sometimes solve tricky, unexplainable problems.

If you get the warning, Primary Scratch Disk Full, your hard drive has run out of memory. The scratch disk uses a portion of your hard disk as virtual memory. That is to say, when you have an image that overflows your RAM, it flows onto your hard drive.

To solve this problem, you should either specify a new scratch disk (if you have another hard drive hooked up to your machine) via File+Preferences+Plug-Ins & Scratch Disks or free up space on your hard drive by deleting unneeded files.

The main thing to remember here is that Photoshop needs memory. Image files are big, and Photoshop itself gets bigger with every new release. Make sure that you have a large enough hard drive to accomodate your work (or removable media, such as Zip or Jaz drives), and above all else, enough RAM. The time you will save will more than pay for the expenditure in memory.


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