VECTOR file be too Low Res?Does Original File Matter?

Discussion in 'Design and Graphics' started by freedomb, Mar 10, 2011.

  1. freedomb macrumors newbie

    Joined:
    Mar 10, 2011
    #1
    I did a job in Illustrator , converted a Photoshop file and then did live trace.
    I thought vectors were beyond dpi. My client is saying, the source DPI must be changed???
    Does anyone know if vector files can differ due to source file? Even after live being Vectorized???

    Thanks,
    Freedom
     
  2. davedee65 macrumors regular

    davedee65

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    UK
    #2
    If the original image had a low dpi , was low res, then the resulting live trace of that image will have jagged edges and a pixilated appearance. If an image has a high dpi, 300+, then the resulting live trace will have smooth edges etc.

    It sounds like your original image was of too low dpi. Are you able to show us the original image and your live trace of it?

    Cheers
     
  3. MisterMe macrumors G4

    MisterMe

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    #3
    Agree with everything that davedee65 said. Also understand that tracing does not produce the end product; its product is much closer to the beginning. Your trace produces a lot of control points. You must now go through and eliminate most of those control points until your zigzag lines become smooth curves.
     
  4. citizenzen macrumors 65816

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    Mar 22, 2010
    #4
    Getting nitpicky here, but...

    DPI (dots per inch) is a measure of printer resolution, is totally dependent on the output device and not the graphics file.

    PPI (pixels per inch) is a measure of a pixel-based graphic's resolution and has nothing to with vector-based graphics.

    Anyways...

    I would also like to see the Illustrator file and am curious to find out what the client means. Somes times it takes a bit of sleuthing to figure out what problems a client is actually trying to describe.

    I am curious why you started in Illustrator, went to Photoshop and then retraced back into Illustrator. What effect were you trying to achieve?
     
  5. dmz, Mar 11, 2011
    Last edited: Mar 11, 2011

    dmz macrumors regular

    dmz

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    #5
    VECTOR file be too Low Res?Does Original File Matter?

    A vector file has no property of resolution - the rendering device determines the dpi/ppi of the final output. If the vector file is "rough" looking in Illustrator at high magnification, then it will be rough no matter the output device, but I don't believe that's the issue - you did look at the file after vectorizing and cleaned it up a bit, as MisterMe pointed out, didn't you? Square corners tend to round off, straight lines sometimes have a bow in them, parallel lines aren't parallel, "skinnies" or gaps appear between objects that share a common edge, etc., etc. Look closely!

    Live tracing a low resolution image - say <100ppi - will amplify these errors. However, increasing the "path fitting" in the Trace options to more than 1 or 2 pixels should not result in your path following the edge of the pixels exactly and producing "jaggies" in your vector result.

    Some clients just like to throw the lingo around (as do print sales people) with no real understanding of the issue or the terms.

    BTW, citizenzen, though the terms ppi and dpi have slightly different meanings in different contexts, your definition is askew. The distinction between DPI and PPI is that DPI refers to a single-bit dot, as in a laser imagesetter whereas PPI refers to a multi-bit entity, i.e an RGB pixel is usually 24-bit-per-pixel(dot). Pixels have depth, dots do not. Cameras have PPI, printers, even those printing in multiple colours, have DPI. The two terms are used interchangeably by most people in the industry, and most of us understand what is meant either way. An image has no "inherent" DPI, it is an artificial and arbitrary measure - i.e. it doesn't matter what the DPI actually is, what matters is how many pixels are in the source image. Not looking for an argument here, and I don't know how this point got in, but let's not make the water muddy with spurious definitions.

    I too would like to see an illustration of the problem...

    dmz
     
  6. Blue Velvet Moderator emeritus

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    Jul 4, 2004
    #6
    Nice to see some wise heads chiming in on DPI vs PPI, one of my pet pedantic peeves. Now for LPI... ;)
     
  7. dmz macrumors regular

    dmz

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    #7
    Pixels, pels, dots and samples

    Don't forget SPI!

    Pedantically,

    dmz

    ;)
     
  8. citizenzen macrumors 65816

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    Mar 22, 2010
    #8
    Dearest dude,

    I believe you repeated what I already said. (albeit with about 4x the amount of words)

    Thanks for agreeing with me.
     
  9. THX1139 macrumors 68000

    THX1139

    Joined:
    Mar 4, 2006
    #9
    A vector file is a vector, is a vector. They are resolution independent UNLESS they have an embedded bitmap. But, if you did a live trace and then deleted the source file, then the resulting (live traced) vector is resolution independent. Meaning, that you can scale it up from postal stamp to billboard size without loss in original quality. However, it might look different when scaled depending on how well you did the original trace.

    The client calling to say that you need to supply a file with a different resolution make zero sense, because a vector has nothing to do with resolution. They don't know what they are talking about so you should get clarification before going further.
     
  10. designguy79 macrumors 6502

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    Michigan
    #10
    I have had this happen multiple times -- I ask for a vector file, and so they save the .JPG (or whatever) into an .EPS or .AI and think its good to go.

    Whats even better is when they just rename .JPG to .EPS... :)
     
  11. MisterMe macrumors G4

    MisterMe

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    #11
    You should respect a specific format like .pdf or .eps rather than a broad category like "vector."
     
  12. THX1139 macrumors 68000

    THX1139

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    Mar 4, 2006
    #12
    For clients, yes. But anyone who knows anything about the industry knows what vector means. EPS, PDF, and the like, are just formats for a specific platform. They are still vector based if they are created that way.
     
  13. dmz macrumors regular

    dmz

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    #13
    Freedom?

    What happened, OP?

    The OP has a simple question, :eek: but was a little unclear in their description, so we ask or clarification. :( Next thing you know we're arguing over the terms, ranting about our pet peeves, over-describing the problem, re-defining definitions we all understand, and... :confused: no response from poor OP.

    We probably scared him away. :eek:

    Come back little feller! ;)

    dmz
     
  14. bocomo macrumors 6502

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    New York
    #14
    Doesn't opening the Illustrator file in Photoshop rasterize the file? There should have been a dialog box asking at what resolution the vectors should be rasterized, right?
     
  15. Kwill macrumors 68000

    Kwill

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    Mar 10, 2003
    #15
    Please clarify

    OP, are you saying your workflow went like this?
    ai -> psd -> ai
     
  16. citizenzen macrumors 65816

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    Mar 22, 2010
    #16
    I had a question about that too. But it is conceivable that he/she was trying to achieve an effect in Photoshop (i.e., ragged edge from a scanned source) that couldn't be duplicated in Illustrator.

    So why start in Illustrator? I don't know... precise sizing/positioning of elements perhaps?
     
  17. davedee65 macrumors regular

    davedee65

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    #17
    I couldn't agree more dmz. The guy just wanted some simple advice and as usual out come the soap boxes!!

    The way I read it, the OP was doing a "job" in Illustrator which involved placing and tracing an image. Said image must have been too low res or too small and so resulting trace was not up to scratch. The client has said that a better quality image be used to result in a better quality vector.

    OP, the quality of your trace will be governed by the quality of your source image. Relying on Live Trace alone is not always ideal, and as has been suggested elsewhere a certain amount of "tweaking" will be required.

    I doubt whether we'll ever find out anymore from the OP because if it were me I'd have given up on this thread ages ago and found my help and advice elsewhere!
     
  18. Razzerman macrumors regular

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    Sep 11, 2007
    #18
    Hello freedomb,

    It sounds as though your client isn't happy with the job that Live Trace did, and I'm guessing that depends on what kind of image you have been supplied. E.g. a monochrome caricature is an ideal candidate for a Live Trace, but a company logo generally won't fare so well. You might need to spend some time adapting / redrawing the parts that Live Trace has failed on. It is hard to make a proper judgement without some further details.

    Cheers,

    Razzerman
     

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