resolutions

[myusuf]

Hi, I want to know about resolutions.. I mean what would be the best resolution for a good out put. Explain me please about aspect ratio. What is it? Is 4000*4000 is a good resln?

[STRAT]

depends what it's final out put is for. You'll generally give yourself a good idea about printing/rendering sizes for any particular image if you ask your client what it's to be used for. how else are you going to know?

 

* if it's just for a web site the around the 1024x768 mark is ok.

* if it's for testing and client work in progresses, then again, 1500 pixels will print out on A4 adequately.

* For brochure or magazine style quality production printing, then 300 dpi is the standard. for A4 size this means rendering at 3508 x 2480 pixels.

* for bill board or site banners, you'll need to ascertain what size the banner will be, then render out at the equivalent pixel size of maybe 75-100 dpi.

 

Generally in our office, we dont always know what the final output will ultimately be used for by the client, so we generally tend to render our finals out at around the 3500-4000 pixel size, unless otherwise instructed.

[myusuf]

Thanks so much for the knowledge.. One more thing what is dpi? and one more thing. i havent understood one thing like, say 800*600 pixels image will be bigger than 4000*4000. If its smaller the pixels bigger will be the size of the image, then why 360*290 or 640*480 is smaller than 800*600. Please explain me in detail if possible....Thanks in advance..

[STRAT]

i'm sorry, i dont understand your english too well to understand your question.

 

but, DPI is very confusing to the person who's never heard of it before. i wouldn't know where to start explaining it in easy terms i'm sorry. perhaps someone else would do a better job.

[mattes]

Hi...

Using dpi is actually easy:

 

how much dpi do you want?

1 inch = 2.54 cm

A0 @ 100 dpi: 120cm / 2.54 * 100dpi = 4.725 pixel

plus height: 85cm / 2.54 *100 = 3.346

=> 15.8 MP

 

A0 @ 300 dpi: 120cm / 2.54 * 300dpi= 14.173 pixel

 

I had rendering 6400x4800 @ A0-OVERSIZE! and you could barely see any pixel even in close-up!

[Nic H]

use print size wizard in max!

[Jeff Mottle]

http://www.cgarchitect.com/vb/5759-printing-resolution-size-dpi-ppi.html

[myusuf]

Thanks every one... I got it now.

[Peter M. Gruhn]

Sorry, this one is extra poorly composed...

 

Was talking with the architect the other day. She had gone to a meeting at the client's. "And we took those renderings and had them printed on 3' posters and hung them up in the lobby." Architect and I each had the same reaction "OMG WTF Gah! How bad do they look?!" Because, you see, they were delivered at 1200 x 600 pixels. A bit of web, maybe a brochure on the office ink jet. I'm told that they look gorgeous. One shows some pixelation and that was the one that would, it has some bad aliasing at high contrast in some parts.

 

Maybe everybody I've heard from is blind? Maybe the printer uprezzed with a fractal resampler (they're.. OKAY... from what I've seen).

 

For my money they barely had enough going just visually to hold at small sizes. As close view wall posters they'll look extra blank and boring. Hey, so long as the client is happy.

 

Anyway, for the OP, make sure you get the difference between "dots per inch" and "pixels per inch" down (and also consider "lines per inch"). The terms will get used interchangably so you often have to guess what is meant by the context.

 

But when it becomes most important is when somebody says "well, our printer does 1400 dpi so you'd better give us a 14000 pixel image or we'll sue" and you don't want to spend a week rendering. Those dots aren't pixels, they are droplets of ink and it takes a number of them to build up a pixel. Increasing DPI helps image clarity. The first Apple Laserwriter was 300 dpi and looked pretty good but you could still see the pixels. At 600 dpi things get pretty darned smooth even on a strictly black or white image. I've seen consumer grade dye sub output which doesn't even really have dots anymore but was only, iirc, 100 pixels per inch and since it was printing photographs looked just fine. By the time a printer is talking 1400 dpi, it's not talking about an ability to render your increasingly smaller pixels invisibly, it's talking about it's own color reproduction ability. Two big cyan dots in an expanse of white make a worse sky than two hundred smaller cyan dots closer together. Six color printers address the same problem - hey, we can put down more dots, filling up more paper making a smoother tone because the ink is fainter.

 

So I always think back to those Apple Laserwriters and the dye-subs. I figure that if I'm trying to print a properly anti-aliased realistic render 300 pixels per inch is good enough, no matter what the printer can do. Do some tests, you'll find you can get away with 150 ppi for a lot of work.

 

Then there's the issue of "subtended angle". Quite simply, how big does a pixel look when viewed from where it is supposed to be viewed.

 

The Sun and the Moon are about the same apparent size of disk in the sky. The Sun is much bigger but much further away. Same problem as printing.

 

Printing a billboard that will be seen from a speeding car from 100 yards away? How big is an inch at 100 yards? About one minute of arc. What's one minute of arc at three feet? 1" / 100. So, if you aim for 300 ppi on the hand held pamplet, you can get away with 3 ppi on the billboard. So, at 48' that's 12*3*48 = 1728 pixels. This was a back of the envelope experiment, but it give you an idea. Or, you could take an 8x10 print, go outside with it, hold it at viewing distance from your eyes and walk towards a billboard until the paper and the billboard are "the same size"; now, if your vision is better than mine, the same number of pixels on the billboard as are on the paper will "look the same" to you. Where are you standing in relation to where the billboard will be viewed? Closer? Then you're good. Further? THen maybe you need more.

 

And if your image is going to be inspected under microscope for the pores on the model's nose then you'll need more pixels per inch ;-)

 

A side note on computer display - watch out for people who tell you "a computer monitor is 72 dpi." That was true in 1984 when the first Macintosh came out and Apple decided to redefine the "point" to be 1/72". The coordinated their screen and their impact printer to the same size and the world was good. Common VGA resolutions on common monitors hit around 96ppi pretty quickly. I've currently got a measly 90 ppi (1680 on 18") because I'm poor. Previous monitor was pushing 115 ppi I think (~2048 on 18"). The upshot of that is be aware that any graphic you target for the web (or other computer viewing) will be viewed at an unknown pixel per inch and an unknown final size. You can only ballpark it. My first web site I went crazy, I put up images at 800x600 pixels and said "bleep the fools without real graphics cards". Those images now look tiny.

[BVI]

Don't get confused between DPI and PPI - PPI (pixels per inch) refers to screen resolution while DPI (dots per inch) refers to print resolution.

 

In terms of PPI - I find that 2500px - 3500px prints up to A0 decently with zero quality loss. Keep in mind to print from an uncompressed JPEG or a TGA, PNG etc as the minute you add compression it decreases image quality.

 

Clients tend to print on really bad paper on a crappy printer at the local printshack (so super high res wont make a difference) - so do the value added service and print it for them in-house or at least at a repro house - so that you can control the quaility of the final prodoct.

[myusuf]

Thanks so much for the details...