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E-publishing graphics with exact dimensions
E-publishing graphics with exact dimensions
CDarling




msg:852202
 12:13 am on Jun 11, 2002 (gmt 0)

I'm going nuts trying to figure out how to publish sewing patterns electronically. The problem is that the patterns are templates and must therefore print at exactly their true dimensions.

The other constraint is that people who sew are often not computer experts, so whatever solution I settle on has to be very, very simple for the user. And has to work reliably on every model of printer, all around the world.

Here's where I need your help:

As far as I can tell, GIF files don't always print at their true size. See my test pattern at [quiltersreview.com...]

When I open the GIF in PaintShop Pro, it tells me it's a perfect 6" by 6". Whether you print the page or click on the link and print just the GIF, you may or may not get a 6" x 6" test pattern. On my printer, I get 4.75" x 4.75".

So my question for you is:

Can I create simple GIF graphics and expect them to print at exactly the same size on everybody's printer, without expecting the user to do anything fancy?

Thanks!

Charlie

 

defanjos




msg:852203
 1:55 am on Jun 11, 2002 (gmt 0)

I think you need to go with PDF (Adobe) files.

CDarling




msg:852204
 11:41 am on Jun 11, 2002 (gmt 0)

PDF files raise a whole separate set of issues that I'm planning to explore in another thread. For right now, I'm just trying to understand exactly how GIF files work.

Can anybody tell me the relationship between the size of a GIF reported in PaintShop Pro and the size at which the image prints? (See first post, above, for details.)

Thanks,

Charlie

korkus2000




msg:852205
 11:51 am on Jun 11, 2002 (gmt 0)

Don't print gifs. They are a horrible format for printing. You want to print at atleast 150 dots per inch. Gifs are 72. Your printer is probably making it higher resolution so it will look better. This makes your picture smaller on paper.

I would make a gif version that people could see on the web but save the actual file to a tiff, pict, bmp, targa, or something more printable. You could even really save it as a jpg just higher compression. Just link from the gif preview to the larger file. This should initiate a download to open in the users own editor. You could even have links to free editors off your site.

Don't trust a browsers to render or print graphics.

rewboss




msg:852206
 3:33 pm on Jun 11, 2002 (gmt 0)

When my mother used to do lots of sewing, she had the patterns spread all over the dining room table, and they were much bigger than could be printed with a normal desktop printer. Plus, of course, they had to be pinned to the fabric, and you can only do that with very thin tissue paper, which you can't feed through a normal desktop printer, much less actually print on.

Then you have the big headache about paper size. While Americans are using paper sizes called "Legal" and "Executive", Europeans are using "A5" and "A4" -- and the height/width ratios are very different (A4 is noticeably narrower and longer than the nearest American equivalent -- if I have to photocopy a letter from America, I have to copy it at about 90% so that it will fit).

Different browsers, printers and operating systems will give different results.

CDarling




msg:852207
 4:04 pm on Jun 11, 2002 (gmt 0)

Thanks!

Re: sewing patterns...these are actually quilting templates, so the pieces are all small (2" to 6") and normal printer paper is fine. Trust me on that.

Re: the printer changing the resolution. This sounds like an important clue!

Does everyone agree that when a typical PC user prints a typical GIF from the typical browser on their typical printer, the GIF will typically be printed at a higher resolution than 72 and therefore appear smaller than it was designed to?

That would certainly explain a lot.

(No offense, Korkus2000 -- I always take a poll on any "keystone" fact like this. I really appreciate your bringing it up!)

Thanks all,

Charlie

mivox




msg:852208
 5:18 pm on Jun 11, 2002 (gmt 0)

Does everyone agree that when a typical PC user prints a typical GIF from the typical browser on their typical printer, the GIF will typically be printed at a higher resolution than 72 and therefore appear smaller than it was designed to?

AFAIK, it depends entirely on the printer and it's driver software. Some printers have "features" that are designed to smooth web graphics when printed, which would affect any gif image...

I would also recommend using PDF format, with the grpahics designed at a minimum 150ppi resolution. 300ppi would be better for detailed images, but I'd imagine quilting templates are mostly fairly simple outline images, so it shouldn't be a problem.

rewboss




msg:852209
 8:52 pm on Jun 11, 2002 (gmt 0)

Incidentally, there is a difference between dpi (dots per inch) and ppi (pixels per inch). The first is used for printers, the second for monitors.

The problem is that graphics editors usually assume that you are working with dots, not pixels; for the web, you will normally be working with pixels rather than dots. Things start to go awry when the browser has to convert from ppi to dpi. How many ppi does the browser assume?

mivox




msg:852210
 9:02 pm on Jun 11, 2002 (gmt 0)

Well, most graphics programs won't do anything in dpi unless you specifically half-tone the image for print. The "DPI" ratings you see for inkjet printers really have nothing to do with the image settings...

Half-toning (and therefore dpi) isn't something you'd need to deal with at all, until you send your image to a professional printing press. In which case, get specifications from your print shop... most of them will just specify a file type & minimum ppi resolution, and can handle the half-toning and color separations themselves.

If you're talking about folks printing your files on their home printers, ppi is the only resolution setting you need to deal with. In that case, any ppi setting high enough to prevent "jaggies" (visible pixellation) in the printed output is good enough. 150 is a good minimum for good inkjet output, in my experience.

But there's no option for such fanciness with GIF format... it's really intended just for on-screen display, and defaults to 72ppi.

Clear as mud? ;)

CDarling




msg:852211
 9:24 pm on Jun 11, 2002 (gmt 0)

Now I'm starting to get it!

1) GIF defaults to 72ppi. (Side issue: Is it possible to have a GIF at other than 72ppi?)

2) Printers think in dpi, not ppi.

3) Therefore, the printer must translate the GIF from ppi to dpi.

4) The assumptions the printer makes about the number of dots per pixel (or pixels per dot) determines the final printed size of your GIF.

If the translation of ppi to dpi were handled numerically the same across most printers, then I'd be all set -- I'd just have to take that conversion into account when I create my GIF.

What do you think? Do most printers translate pixels to dots the same (numerically)?

mivox




msg:852212
 9:55 pm on Jun 11, 2002 (gmt 0)

2) Printers think in dpi, not ppi.
3) Therefore, the printer must translate the GIF from ppi to dpi.
4) The assumptions the printer makes about the number of dots per pixel (or pixels per dot) determines the final printed size of your GIF.

I'm not sure about those points. Some printers actually advertise a feature for
"smoothing" web graphics... others don't. I've never had a problem with my Epson printers changing the dimensions of GIFs though.

I don't think, however, that there is anything as specific as an actual "dots per pixel" number. The printed "pixels" in a 300ppi 2x2 image would be much smaller than those in a 72ppi 2x2 graphic... as the 300ppi image would be 600pixels x 600pixels in that two inch space, while the 72ppi image would only be 144p x 144p... so the printer wouldn't really be able to have a simple "dots per pixel" conversion.

The printer probably doesn't "think" in dpi at all. In conventional printing (such as newspapers & magazines), DPI refers to the number of halftone dots per inch in a "screened" image. Inkjets don't use halftone dots, and I'm honestly not sure what their "dpi" rating means... it could be the number of halftone dots they can print per square inch before the dots get blurry and bleed together, but I really don't know.

I don't know of any way to create a GIF at higher than 72ppi. Check to see if your printer's settings have some kind of "smoothing" option you could turn off.

Also, double check the pixel dimensions of your GIFs... ignore the "inches" measurements your software is giving you. If you want a 4" x 4" printed image from a 72ppi GIF file, the file should be 288 x 288 pixels...

MaliciousDan




msg:852213
 10:25 pm on Jun 11, 2002 (gmt 0)

Put a ruler on all of your graphics so someone can hold a ruler up to the monitor and compare the size of an inch on screen (and then provide links to several different sizes of the image so that different resolutions print correctly).

volatilegx




msg:852214
 10:58 pm on Jun 11, 2002 (gmt 0)

I believe you can save a GIF graphic in any resolution. However, the higher the resolution, the larger the GIF will appear when it is displayed on the screen (like in a browser).

The problem is, Macs display at 72ppi and Windows displays at 96ppi. Also, most printer not will print truly accurate measurements, because they are too dependent on software drivers. About the only printers you can depend on are PostScript printers, because they all use similar drivers. Most people don't use PostScript printers, because they are more expensive.

I heartily recommend using PDF format because:

1) The format is compressed and downloads quickly.

2) You can use Page Layout Software to create the patterns, such as PageMaker, to assure you the most accurate measurements possible. With page layout software, you can resize the graphics to any size you desire.

3) Acrobat is a worldwide standard for compatibility in documents. Almost everybody uses it. The reader is freely downloadable from adobe.com.

4) It would be very easy for unexperienced users to use.

OhMyPixel




msg:852215
 11:04 pm on Jun 11, 2002 (gmt 0)

Correct me if I am wrong BUT, I believe there are also scaling options in most browsers under FILE>PRINT. Not only will you have size conversion problems with the .GIF file but sometimes printers are set at 80% or so to make sure that web pages fit on the width of the paper. This could really throw off your graphic as well. It seems like this could create another problem if you are not careful - Being that this is something that your visitors are probably not going to be savvy enough to change (according to your post).

<non expert opinion>I say PDF all the way.</non expert opinion>

Grumpus




msg:852216
 12:04 pm on Jun 12, 2002 (gmt 0)

Seems to me that you simply put the gif into a standard document (i.e. a Word File - or an RTF file for cross platform compatibility). Since you save the page layout along with those it's simply a matter of embedding your image (set it to "stretch" so resolution is irrelevant) into the page (set it up for a standard 8.5" x 11.5" piece of paper.) If someone changes the size of the paper, your embedded image will still maintain its size unless they physically change it.

This should work, and since it's merely a pattern and not a work of art, you could probably get away with an image designed to print at even 3 inches and stretch it to 6 in the document and it'd still work because the contents of the page hasn't changed, just the available print area.

In answer to a previous question, yes, GIF files can be of something different than 72, but GIF's are mainly for onscreen viewing, not printing - they'd use TIF or TGA files for quality printing.

The key here is that you're looking for a small file size (GIF's are fine, JPG's might be better) but printing gets fishy when you try to print them raw because your printer will try to make best use of the page, by default. By saving it into a formatted document designed to be printed, you eliminate that headache.

[edited afterthought] Oh, and yes, they're right about PDF files, but you're looking at buying and learning new software. You should be just fine if you use word or some other word processor.

G.

HyperGeek




msg:852217
 1:10 pm on Jun 12, 2002 (gmt 0)

This is stupid simple:

72 dpi = Web Graphics

200, 300, 600, 1200, etc. dpi = Print Graphics

Go into any graphic editor and change the dpi to 300.

Then change the dimensions of the graphic from pixels to inches.

Most graphics will be something like "40px X 45px".

Change this to the size of the swatch/pattern, "2in X 3in".

Remember, for a graphic to print - it really only needs to be the right dimensions measured in inches. For it to print in better quality, the graphic should not only be measured in inches, but it should then be a higher DPI (dots per inch - 300 is standard, 600 is high-quality for logos and such, 1200 and up is usually used for industrial print jobs).

Nice! I'm now a full member. :)

mivox




msg:852218
 5:08 pm on Jun 12, 2002 (gmt 0)

The original problem was that her graphics editor was telling her the image was one size, but her printer was printing a smaller image. If your image editor says the image is 3" x 3", and your printer is producing a 2.5" x 2.5" image, you've got a bit of a mix up somewhere...

So if you want to make absolutely sure all of your users get the image to print at 3" x 3", giving them a raw gif image probably will not do the trick, given the vagaries of modern printer drivers and default scaling options that novice users may not be aware of.

rewboss




msg:852219
 5:34 pm on Jun 12, 2002 (gmt 0)

CDarling's graphics editor is making an assumption about how many pixels there are to an inch on her screen. That relationship depends on the size of her screen and the resolution. If she has her screen resolution set to 800x600, and her screen is exactly 12 inches wide, that means there are 66.67 pixels to every inch. Change the resolution to 1024, and now there's 85.33 pixels per inch. But the graphics editor can't tell how big the screen actually is, so assumes 72ppi.

The printer driver, though, is probably working at 300dpi. That means one pixel becomes 4.167x4.167 printer dots. But you can't have 0.167 of a dot, so the printer makes it 4. That's probably where the error comes from, and the reason why the image prints out smaller.

Change to 300dpi, and it should work -- if the user has his or her printer set to 300dpi.

A printer dot is the smallest dot a printer can print. For an inkjet printer, it's easy to visualize: the dot made by the smallest drop of ink the hardware and software will allow. 300dpi is fairly normal, and the dots are much smaller than the half-tone dots in newsprint -- but they're still dots.

Some browsers running on Windows had a problem when printing out text in sizes specified in pixels: they simply translated pixels into dots. Text specified as 12px printed out as 12 dots high -- at 300dpi, that's illegible. That now doesn't affect many people, but for a while px were, for that reason, not a recommended unit of measurement in CSS.

Incidentally, I can create GIFs of 300dpi and more with my graphics editor. At that resolution, an image 800x600 pixels (a screenshot, say), fills the entire screen, but prints out at 2.67x2 inches.

[edited by: rewboss at 5:43 pm (utc) on June 12, 2002]

mivox




msg:852220
 5:41 pm on Jun 12, 2002 (gmt 0)

Incidentally, I can create GIFs of 300dpi and more with my graphics editor. At that resolution, an image 800x600 pixels (a screenshot, say), fills the entire screen, but prints out at 2.67x2 inches.

OK. So it IS possible, but there isn't much reason to use GIF for high-res work... Thanks for straightening that out! If I'm working high res, I always just use TIFF.

I wasn't sure if inkjet printer DPI ratings were actually referring to the ink droplet size, because when I look at an inkjet print these days, the printer specs may say 1200dpi, but it sure looks like you could fit more than 1200 of the ink drops into an inch...

Do you happen to know if inkjets are measured by how many droplets per inch they can produce without them bleeding together? Or what specific measurement is used? I've never found DPI measurements to be any use for anything except halftone screens, just because no other application of the measurement seems very standardized.

korkus2000




msg:852221
 5:58 pm on Jun 12, 2002 (gmt 0)

I think the point is made that she should not use gifs. There are to many variables involved. Your best result would be PDF. If you can't do that try another format. Gifs were really created for lossless compression for images less than 256 colors. They were ment for images to be very small. If you are going to make a gif above 72dpi then I suggest using png.

What you are trying to do, as you can see, is a tough one on the web. Thats why the folks at adobe created PDF. It is used for exactly what you are trying to do. Really anything else is going to be a hack.

also paper quality and the actual ink/toner does matter. I have seen inkjets print at 1440 dpi. They have no comparisson to 600dpi from a fiery. There are a lot of variables when it comes to printing. Thats why I am a web designer. Its much easier than print. No gamut and stuff like that.

Does paintshop pro not have a print size view like photoshop?

rewboss




msg:852222
 6:20 pm on Jun 12, 2002 (gmt 0)

Do you happen to know if inkjets are measured by how many droplets per inch they can produce without them bleeding together?

Whether or not the dots bleed together depends not just on the closeness of the droplets, but the quality of the ink and of the paper. Once you're in the 1000+ region, you're looking at high-quality photos printed on special glossy paper. You might need that sort of resolution if you're a professional photographer.

mundonet




msg:852223
 1:54 am on Jun 13, 2002 (gmt 0)

You could also add a scale to your image and a grid in the backgground, see this washer part page [repairclinic.com] for example.

Ed_Gibbon




msg:852224
 7:09 pm on Jun 14, 2002 (gmt 0)

I think working PDF files are the best solution. I use PDF a lot to make copies of HTML texts, though I have no experience in putting images in PDF. However, here is a thought:

Along with every image in the PDF file, include an image of a ruler showing inches and centimeters. That way the user who prints it can compare the ruler image to a real ruler to verify that the printed pattern is the correct size -- AND (this is where I feel really clever), if the printed pattern is not, most photcopiers will enlage/reduce by percentages (e.g., 92%, 105%) which, with a little trial and error, could be used to make a photocopy exactly the right size. If the pattern is a black-and-white line image, a second-generation photocopy would probably be okay.

ebynum




msg:852225
 1:59 pm on Jun 17, 2002 (gmt 0)

Somebody mentioned that there would be an issue learning an additional piece of software to create the PDF document. Fine Print [fineprint.com] offers a product called pdfFactory that you install on your computer as a printer. When you need to create a PDF, you simply print to the pdfFactory printer, type in a filename, and save your PDF.

Edward

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