In article , "Thomas"
wrote:
…
My lovely wife had saved then as Photoshop 2 files. I just went to her mac and saved the files as tiffs, problem solved…
Still I’m curious as to why these files have no extension
Apple computers use an OS that doesn’t require the user to append extensions to their file names. Any application developed for a Mac automatically includes the file type in the resource fork in the header of the file it creates. When the OS later opens this file, it looks in the header, checks the resource fork, determines the file type and launches the appropriate application based on this information.
The real question is why over 95% of the microcomputer users still need to deal with extensions.
The answer is that they are using an OS made by Microsoft called Windows XXXX. Earlier versions of Windows were shells built around an OS called MS-DOS so that the computers would look/feel more like a Mac. MS-DOS itself was based on an earlier OS called CP/M (some say it was stolen from the creator of CP/M but it’s a little more complicated than that see:
http://inventors.about.com/library/weekly/aa033099.htm)
CP/M was the OS of choice among the small number – compared to today – of "serious" microcomputer users in the 70’s (mostly small businesses). It was designed for the 8-bit microprocessors that were used in the computers at that time and it had all the bells and whistles that you still see today when you get down to the nitty gritty of current Windows-based, 16-bit PCs – including the "8.3" file name constraint with it’s 3 letter extension.
During this same period of time, microcomputers were being developed by entrepreneurs for the home market (Apple II, Pet, Amiga, Atari, TRS 80, etc.). Each of them came with their own version of an OS. Apple was one of a number of companies whose OS did not require file name extensions and it continues that tradition to this day (almost from the start, file names up to 256 characters in length were allowed by Apple’s OS and others at the time).
As you discovered, applications that run on a Mac, like Adobe’s PS, are smart enough to know that, in the real world, files will often find their way to computers that use MS OS. Their default setting is set so that any file saved by the application has the appropriate extension appended to it’s name.
Lucky you. Dragging the files needed to a single folder/directory and doing a batch-save to a tiff file to the same (or another) folder/directory solves the problem of converting Mac savvy PS files to PC ones.
ron