8 Replies Latest reply on May 8, 2010 6:15 PM by bpylant

    Placing Images With Different DPI's In The Same Illustrator Document?

    ghetto3jon

      I'm constructing an Illustrator document for compact disc manufacturing. It consists of a simple background image (made in PhotoShop at 300dpi), and "text" with effects on it (also created in PhotoShop, essetially more graphics...just with a trasparent gackground). The background image is 300dpi, and there is nothing I can do about that...so I "place" that image into Illustrator. Done. But with the effected text, I can create that at whatever resolution I want. So is it a wise idea to construct the "text" in PS at a higher resolution (1200dpi?), and then place that into Illustrator document?

       

      In other words, is it safe to make an Illustrator document that contains some graphics done at 300dpi, and others done at 1200dpi?

        • 1. Re: Placing Images With Different DPI's In The Same Illustrator Document?
          Jacob Bugge MVP & Adobe Community Professional

          jon,

           

          So is it a wise idea to construct the "text" in PS at a higher resolution (1200dpi?), and then place that into Illustrator document?
          Wiser than having text at 300 PPI, maybe not wiser than creating it in Illy.

           

          In other words, is it safe to make an Illustrator document that contains some graphics done at 300dpi, and others done at 1200dpi?

          It is. Depending on version, you may have to resize to get the combination of resolution and size right.

          • 2. Re: Placing Images With Different DPI's In The Same Illustrator Document?
            Wade_Zimmerman Level 6

            you sort of have this a little off kilter.

             

            if your document in photoshop is 300 ppi anything you place or copy into it ill be 300 ppi come hell or high water as long as you keep your computer cool and dry.

             

            if you place the text from a document that is 1200 ppi it will resize and become 4x the dimension in the 300 ppi file.

             

            so it is a waste of time and effort.

            • 3. Re: Placing Images With Different DPI's In The Same Illustrator Document?
              ghetto3jon Level 1

              re: wade...

               

              ...but i'm talking about placing PS into Illustrator. they retain their DPI, right?

              • 4. Re: Placing Images With Different DPI's In The Same Illustrator Document?
                JETalmage-71mYin Level 3
                I'm constructing an Illustrator document for compact disc manufacturing.

                 

                The first thing you need to know at the start of any print-destined project is what kind of printing technology you are designing for. CDs may be screen printed, heat sublimation imprinted, rosin imprinted, or even laser-etched. The hardware resolution and screening method to be used is what you base your image resolution upon, depending in turn upon the nature of the artwork. Is the artwork continuous-tone, line art, or a combination of both?

                 

                Your description doesn't answer any of these questions.

                 

                It consists of a simple background image (made in PhotoShop at 300dpi)

                 

                And by what rationale did you determine that 300 ppi was appropriate? The conventional-wisdom mantra that "all raster images should be 300 ppi"? I'm not being a wise guy here. I'm trying to explain that there is no one-size-fits-all set of rules for optimum printing results without first defining both the nature of the artwork (color depth, number of colors, spot color, process color, line art, contone) and printing method. If you don't know these things, and don't know why they matter, you should at least talk to the printing house for advice. Frankly, in this forum you are just as likely to receive bad advice as good.

                 

                and "text" with effects on it (also created in PhotoShop, essetially more graphics...just with a trasparent gackground).

                 

                What kind of effects? Are we talking about 6 pt. text listing the files on the disk, or headline artwork with fuzzy soft-edged effects like the ubiquitous drop shadows or faux emboss?

                 

                The background image is 300dpi, and there is nothing I can do about that...

                 

                Of course there's something you can do about that. The question is whether you need to.

                 

                so I "place" that image into Illustrator. Done. But with the effected text, I can create that at whatever resolution I want.

                 

                Okay, so not knowing any pertenent specs for the project, let's assume you do need a 300ppi background image. Let's further assume this will be a full color continuous-tone image to be printed on a white underprint (not on the bare shiney surface of the disk itself) using traditional CMYK halftoning with translucent inks. (We'll disregard the fact that assuming large quantity reproduction, that scenario would likely involve a halftone ruling much courser than any that would acutally require 300ppi.) Let's further assume your "effected" text refers to raster effects applied in Photoshop.

                 

                In that case, there is no reason for the text to be imported into Illustrator as a raster object separate from the background image raster object. You've said you are building the raster effect text in Photoshop anyway. So build it on a layer in the same Photoshop file as the background art. When happy with it, flatten it to a single-layer image. If there's no Illustrator-created objects to be added to the design, then why do you think it necessary to import it to Illustrator?

                 

                So is it a wise idea to construct the "text" in PS at a higher resolution (1200dpi?)

                 

                The only time you would need to do that is if the text were to be printed as line art, and if the printing device itself were capable of printing 1200 spots per inch, and if the printing device were not capable of printing anything other than raster input. Otherwise, if your text is vector, leave it as vector, and deliver it as a PDF file or some other meta format that the printing device can understand.

                 

                Look...line art--artwork (including text) that is to be printed as a solid color in order to obtain edges as sharp as possible--is optimized by utilizing the basic mechanical resolution of the printing device. In other words, it is rendered by simply turning on and off the tiniest printer spots that the imaging device is capable of drawing. In a nutshell, that's the purpose of vector graphics. In the scenario you have only vaguely described so far, that would be appropriate for any ordinary text on the label, especially tiny 6 pt. text listing copyright info, etc.

                 

                But not for any "artsy" text such as you have described. Anything that involves continuous-tone raster effects is going to be made up of tone dots (either halftone or stochastic dots). Those dots are built up from the printer spots. Worse, a separate array of those toning dots are built up on each color separation involved, and those separate color plates are printed on top of each other. All of this necessarily involves compromising the actual sharpness possible if you were simply printing a line-art image by turning on/off the printer spots. So if 300 ppi is appropriate for a particular CMYK process printing method, then there is no benefit at all inherent in sampling raster-stylized "text" at a higher resolution, just because your human mind considers that part of the artwork to be "text." Functionally, it's just another continuous-tone raster image. And therefore, there is no reason (other than laziness) for it to be separate from the "background" raster image--it can all be the same raster image.

                 

                In other words, is it safe to make an Illustrator document that contains some graphics done at 300dpi, and others done at 1200dpi?

                 

                A vector drawing / layout program like Illustrator creates and arranges separate objects, not just pixels. Those objects can be any combination of raster images, vector paths, or text. Each individual raster image can have a different resolution. If you apply raster effects to vector objects, you are, in fact, creating addtional raster images, quite possibly at a different resolution.

                 

                Whereever separate raster objects overlap, if they involve so-called "transparency" (like drop shadows, etc, etc.), then when printed the whole thing--somewhere along the line--gets "flattened" to either a single raster images or multiple raster images that abut each other. Nowadays, too many designers just trust that flattening to the automated "decisions" of the built-in raster effects features. They just willy-nilly apply such effects with no thought whatsoever about how it is acutally going to be rendered.

                 

                Then they cry bloody murder when they see obvous "stitching" artifacts where automatically-generated raster images abut perfectly so far as mere position is concerned--but still result in ugly visible edges because the pixel patterns and/or colors don't align right. Mathematically, the program thinks the abutting images appear "seamless." But it's not the program that has to look at the dang thing. The human eye sees an unsightly "giveaway" edge.

                 

                So even with all the willy-nilly raster and transparency features, it's still the safest route (read "best practice") to simplify, simplify, simplify the final construction of your layouts to the fewest and most straightforward set of objects before sending it to the printing device. In other words, you take control of the rasterization decisions.

                 

                If you desire professional results while minimizing unhappy and costly surprises, understand the difference beween raster and vector graphics, have at least a conceptual understanding of the color separation and halftone processes, know the printing method you are designing for, and build the file appropriately for that printing method. A user forum like this is arguably the worst place to try to gain such an understanding. At the very least, get specific advice from the printing house that will be manufacturing the CDs. If they can't provide that, consider hiring an experienced designer to do it for you, or to train you, or to at least take your files and properly prepare them for printing.

                 

                JET

                 

                 

                • 5. Re: Placing Images With Different DPI's In The Same Illustrator Document?
                  ghetto3jon Level 1

                  "And by what rationale did you determine that 300 ppi was appropriate?"

                   

                  it's a digital photo, with a native resolution of 300dpi. so i didn't determine 300dpi, the photo did.

                   

                   

                   

                  "What kind of effects?"

                   

                  the "text" has a little median effect blended on a duplicate layer.

                   

                   

                   

                  "You've said you are building the raster effect text in Photoshop anyway. So build it on a layer in the same Photoshop file as the background art. When happy with it, flatten it to a single-layer image. If there's no Illustrator-created objects to be added to the design, then why do you think it necessary to import it to Illustrator?"

                   

                  if i place the background image and rasterized text as separate objects in illustrator, i have the freedom to move the text around in the illustrator template provided by the manufacturer without having to go back to the PS file. also, there are non-PS elements, like non-rasterized effected PS text (just normal next within illustrator).

                   

                   

                   

                  thanks for the advice.

                  • 6. Re: Placing Images With Different DPI's In The Same Illustrator Document?
                    Wade_Zimmerman Level 6

                    300 ppi is fine and the requirements of quality process print is between 300-355 ppi.

                     

                    So it is fine. the resolution of image has some but not a lot of bering on the dpi output to an imagesetter if you are going to a coarser screen.

                    • 7. Re: Placing Images With Different DPI's In The Same Illustrator Document?
                      PrepressPro1 Adobe Community Professional

                      The basic rule of thumb is, resolution should be 1.5 times the line screen. Example: If your print provider printed at 150 lpi screening the file should be minimun of 225 ppi.

                      • 8. Re: Placing Images With Different DPI's In The Same Illustrator Document?
                        bpylant Level 2

                        "it's a digital photo, with a native resolution of 300dpi. so i didn't  determine 300dpi, the photo did."

                         

                        That is not exactly true. The image has a native resolution, but it can only be measured in total pixels, not PPI -- pixels per inch is irrelevant until you determine a specific output size. For example, an image that is printing at 5" x 5" at 300ppi would have an actual resolution of 1500px x 1500px (5 times 300). No matter how large or small you print the image, the actual resolution stays the same: 1500 x 1500 pixels.

                         

                        So, your photo is 300ppi at a specific print size.  (And note that it's ppi, not dpi -- there are no dots in  your file, only pixels.) But does that match the size you're actually planning to use it? If you enlarge it the ppi will decrease, and if you reduce it the ppi will go up.

                         

                        Oh, and to answer your original question, there is nothing that limits you to a single resolution for images placed into Illustrator. You can place ten images at ten different resolutions, Illustrator won't care one iota.