[birdman]

Could someone explain to me what a "Photoshop EPS" is, and why it's even called an EPS? A normal EPS is a vector graphic, but Photoshop EPS files are not. What is the point of having the option to save it as this type of file when it's not what it appears to be? Is it just an EPS file with a bitmap graphic embedded?

[chabig]

Yes, it's an EPS file with an embedded bitmap. EPS stands for Encapsulated Postscript. Postscript can deal with both bitmaps and vectors. Of course, bitmaps don't scale the same way vector graphics do.

Chris

[birdman]

Originally posted by chabig:
Yes, it's an EPS file with an embedded bitmap. EPS stands for Encapsulated Postscript. Postscript can deal with both bitmaps and vectors. Of course, bitmaps don't scale the same way vector graphics do.

Chris

OK, that's what I figured. Thanks for the quick reply!

So... if I were using QuarkXPress, or Freehand, or (shudder) PageMaker, does it really make a difference whether I use Photoshop EPS, TIFF, or high-quality JPEG (other than file size)? This is assuming I'm printing to a PostScript printer, not some desktop inkjet.

-birdman

[chabig]

I'm not a graphics pro, but I don't think it matters. I think some software simply deals with some formats better than others. That's why you have those options available.

However, Quark and Pagemaker are capable of some simple bitmap editing, I think. You might not be able to take advantage of those features if you're using EPS. I'm not sure, though.

Chris

[teszeract]

If you try the different options and then place the image in your target programme, oyu will see diffrences in the display of the preview. I suspect that the preview of the postscript differs.

[bluedog]

EPS stands for Encapsulated Post Script which is a page specification language for imaging graphics. It can wrap bitmap/raster information into its vector-based format which can be confusing for some people who hear EPS is a great format because it is scalable.

The Photoshop EPS, will preview like any EPS in Quark as a low-rez preview which makes it difficult for on-screen viewing and alignment.

Photoshop EPS can contain vector paths (clipping paths) and other vector data. Photoshop 7 really takes advantage of this will its new 'shape tools' that are vector data (paths) with fills of color or patterns.

Text is also held as vector in PS7 if you save as an EPS. This is a huge advantage of maintaining its quality no matter the resolution of the image or scaling. It WILL NOT smoothly scale everything that's already raster (bitmapped).

Vector-based EPS files are quite compact in size and usually scale excellent from very small to extremely large sizes.

The ADVANTAGES of EPS formatting is its vector capabilities as well as its ability to describe SPOT colors or 'solid ink' colors if you are having something printing on a professional press. Other formats do not allow the saving of Pantone or other spot color-matching systems.

If you want to put spot colors onto a graphic that is already bitmapped, you likely will use the EPS format for saving the bitmap and the 'multi-channel' mode in photoshop to create a channel for the spot color you like.

Look for tutorials on how to create spot color channels in a great book, I highly recommend, called "Real World Photoshop". It is not for the neophyte, but a novice to amateur photoshop geek will find reading this book like enjoying a great novel. Each section has more 'meat' to consume and understand for using Photoshop and its professional features.

Good luck with your projects! Hope I made this explanation clear enough to understand.

[birdman]

Originally posted by bluedog:
Good luck with your projects! Hope I made this explanation clear enough to understand.

Yes, that helped a lot. I figured Photoshop was just creating a bitmap image inside what I normally think of as an EPS. Now that I think about it, when you export a page as an EPS from Quark, it basically does the same thing Photoshop is doing. I guess I only thought of EPS as being vector-based because that's how I think of PostScript, but that's a simple mistake as well.

The reason I asked is because at work, in the past when my boss designed something, he'd create an image in Photoshop but save it as an EPS, which didn't make sense to me since there was no vector data in it, just a photo.

However, you brought up a good point I hadn't thought of before: I can use Photoshop EPS to embed text and lines/shapes and carry it over to another program and still retain scalability. I'd also like to see if including paths in a Photoshop EPS works better for eliminating white backgrounds in Quark, rather than using TIFFs with alpha channels to dictate the clipping.

Thanks!

-birdman

[bluedog]

It CAN be said that EPS files handle color better under some RIP or other conditions. With a color copier using an EFI Fiery RIP using a TIF placed in Quark, I was getting clipped resolution due to scaling the image whereas the EPS didn't when handled by the RIP.

Clipping paths in Photoshop are more precise and give you exact control of where it will clip. Quark uses an algorithm to figure out its path which works well for some things, and horribly on detailed images or ones with low contrast on the edges. The alpha channel gives you fair control but again Quark decides how to adjust the path from your channel to create a clipping mask.

Originally posted by birdman:
Yes, that helped a lot. I figured Photoshop was just creating a bitmap image inside what I normally think of as an EPS. Now that I think about it, when you export a page as an EPS from Quark, it basically does the same thing Photoshop is doing. I guess I only thought of EPS as being vector-based because that's how I think of PostScript, but that's a simple mistake as well.

The reason I asked is because at work, in the past when my boss designed something, he'd create an image in Photoshop but save it as an EPS, which didn't make sense to me since there was no vector data in it, just a photo.

However, you brought up a good point I hadn't thought of before: I can use Photoshop EPS to embed text and lines/shapes and carry it over to another program and still retain scalability. I'd also like to see if including paths in a Photoshop EPS works better for eliminating white backgrounds in Quark, rather than using TIFFs with alpha channels to dictate the clipping.

Thanks!

-birdman

[spiznet]

Originally posted by birdman:
<snip>
However, you brought up a good point I hadn't thought of before: I can use Photoshop EPS to embed text and lines/shapes and carry it over to another program and still retain scalability. I'd also like to see if including paths in a Photoshop EPS works better for eliminating white backgrounds in Quark, rather than using TIFFs with alpha channels to dictate the clipping.
Thanks!
-birdman

The only file format that uses the resolution independent "clipping path" created by the pen tools & path menu is the Photoshop eps format.

(I'm just checking) ...with versions 6 & 7 you are also correct that the vector shapes and text are saved as vector data in the Photoshop eps format. Usable in Illustrator or Quark... Learn something new every day!

[birdman]

Originally posted by bluedog:
It CAN be said that EPS files handle color better under some RIP or other conditions. With a color copier using an EFI Fiery RIP using a TIF placed in Quark, I was getting clipped resolution due to scaling the image whereas the EPS didn't when handled by the RIP.

Clipping paths in Photoshop are more precise and give you exact control of where it will clip. Quark uses an algorithm to figure out its path which works well for some things, and horribly on detailed images or ones with low contrast on the edges. The alpha channel gives you fair control but again Quark decides how to adjust the path from your channel to create a clipping mask.

I'm also using a Fiery RIP on a color laser. I hate doing the alpha-TIFF-clippingpath thing in Quark, for the reason you just stated. Sounds like Photoshop EPS may do just what I wanted. The only real difference may be how it looks in Quark before I print it.

Thanks

-birdman