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jpg vs. png

hankd

which file type is better for saving the images in a portfolio that will be printed. by "images" i mean both the works presented on the pages, and the pages themselves which are saved as images. i saved mine on jpg with minimal compression, and you can't notice any quality reduction unless you zoom into 1000% on photoshop and do a careful comparison (even then, the quality is basically the same).

 
Dec 11, 09 8:46 pm

pdf

Dec 11, 09 10:02 pm
hankd

pdf = huge quality loss even without image compression

Dec 11, 09 10:06 pm
hankd

i think jpg is best since it is visibly the same as png (when not zoomed into microscopic levels) but half the file size

Dec 11, 09 10:08 pm

i was being smart ass - sorry. jpeg is lossy. png is supposed to be a good format but i don't use it generally.

tiff is standard for magazines, but really large. we have our photographer give us images in raw and tiff format then adjust to match the project.

if we are printing things ourselves we make portfolio projects into pdfs (using in-design) and keep them at hand. it is the easiest way to manage data for us.

for magazines we keep a folder full of tiffs, for internet we have a separate folder full of jpegs. no pngs, but that is more inertia than anything....

Dec 11, 09 10:58 pm
Distant Unicorn

PNG = portable network graphic.

It's an image format similar to jpeg except that the file is "interpolated."

This basically means the compression algorithm runs in passes.

Jpgs tend to load at one once from top to bottom in lines.

Pngs load from top left to bottom right in lines. It loads several layers of these line progressions. It then interpolates out and blends the "passes (layers)" together.

If the acronym isn't a dead hint, PNGs were invented for quick file viewing over a network. Because PNGs load in passes, loading the entire file isn't necessary for previewing it.

That being said, PNG is still rather unsupported in postscript (meaning indesign, printers, other layout programs and other publishing software usually won't correctly read it).

And unless you're diehard about using PNGs (Basically, if you masturbate to linux manuals), making a cmyk png is next to impossible.

You will need your files in CMYK format if you're taking them to a professional printer or printing them yourself on a high-quality laser/wax/sophisticated inkjet printer.

While TIFFs and RAWs are good file formats, they're misleading. Both have a "jpeg" preview file. This basically means that they contain all of the raw data (none of it gets stripped between saves) in a bitmap-like format... but that data is used to produce a compressed jpeg-like image.

Think of it as a cereal box. You see and print the cover but there's still stuff in the box.

A lot of people still refuse to work in CMYK or to work in CMYK properly. By properly, I mean that all your colors in CMYK mode must be comprised of no more than two CMY (cyan, yellow and magenta) colors and K (key/hodechrome/black).

If you do a basic conversion, photoshop will match colors based on gamut (display and perception).

So a jewel tone purple without any color correction would be C71 M88 Y 11 K 12.

A corrected jewel-tone purple would be 65C M100 Y0 K5. See, yellow has no business being in a purple color unless you're making a mauve (peach).

Brown, Orange and other complex colors are often 4 plate colors are generally okay but it is best to avoid using them.

Dec 11, 09 11:16 pm
Distant Unicorn

Also, err on the side of caution... if you use pngs, there is a highly likely chance you will cause a press to melt down.

If you have these printed professionally and an error in your pdf file makes the printer freeze, it will take between 5-15 minutes for a big press to full cycle, have the jams removed out of it and set back up for printing.

And you will be charged for press downtime because it was your file that did it.

Dec 11, 09 11:22 pm
ff33º

Orochi are you some kind of genius or something?

Dec 12, 09 1:55 am
aspect

orochi> u are wasted to be an architect^^

Dec 12, 09 8:28 am
aspect

or hanground with us^^

Dec 12, 09 8:28 am
aspect

typo> or hang around with us^^

Dec 12, 09 8:29 am
hankd

tiffs are good quality but they have very large file sizes but they seem to keep the layers in photoshop, which i don't want (i just want an image)


also, i didn't know i had to use cmyk color for professional printing. why can't it be rgb color? will they convert the docs from rgb to cmyk color for me? if so, will the quality be reduced? because i notice when i convert any of my rgb color docs in photoshop to cmyk, there is noticeable reduction in quality - mostly, the colors seem to become less saturated and brilliant. i hope that won't be the case here.

Dec 12, 09 8:38 am
LML

one thing png's do that jpg's don't is support transparency. Orochi, good to hear the potential problems though

Dec 12, 09 9:22 am
trace™

TIFFs can have layers or not (a few years ago there was not an option for layers). TIFFs can be compressed with their lossless codec (unlike jpegs, that are lossy).



Your printer can convert from RGB to CMYK for you, but I always do it myself. Offset printing will be CMYK and if you want complete control, you'll need to create the CMYK file yourself (it just mutilates blues/purples, personally I can't stand CMYK).

You'll need to play with the vibrancy, saturation and other things to try to match the RGB file.

If you are printing yourself, you won't need to.



Also, if you want to get really accurate, you'll need the printer's printer color profile to get things more accurate (and possibly the specific profile for the paper type). PS has most of the more common printer's profiles installed.






Dec 12, 09 9:55 am

thats right LML! transparency in png is very coolio.

i don't use png for most work. like orochi says it isn't supported everywhere. but i do use it on my website to place our company logo with a transparent background on a layer in dreamweaver. is awesome cuz it means i can change background image using random selection from folder and the logo can just sit by itself on top. i love that function. didn't work with other formats.


@hankd. cmyk is printing standard. RGB is what your computer screen uses. colors mix differently when made from light and when made from pigment. so you just have to live with it....it's physics.

that said, most desktop printers work fine nowadays printing from rgb. it is only an issue with proper offset printing. so don't sweat it. you should however be completely comfortable with the possibility that your portfolio will look slightly (or even a lot) different than your screen when it is printed. unless you match your screen colors to the ambient lighting in your room as well as your printer there will always be a difference.

Dec 12, 09 7:52 pm
hankd

are most professional prints done digitally or offset now, i thought iwas digital

Dec 12, 09 8:21 pm
jpg4png

Between JPG and PNG, we go to select PNG image format. This is a good format for everyone in image quality. Convert jpg to png with online tool: jpg4png.com


Sep 11, 19 5:37 am

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