Hey all,
We are about to create a hd version of a game of our and am not sure how to set up my photoshop screen res.
Do i make a 480 320 pixel size with 320 dpi?
or do i just make it 960 by 640 pixels with 72 dpi?
thanks much,
Chris
960 by 640 pixels with 72 dpi.
Retina Display’s 326 dpi is only the approximate density value for the human eye.
A pixel based screen is always 72 dpi.
long story short : you will have the best control over your final pixels with 72 dpi.
If you haven’t done that yet, try your current game on the ipad with ipad target. That gives you a feel of the performance you can expect with your current assets. Can save you a lot of time if you realize that you are doing more than the fillrate even remotely allows to do. (you have slightly more pixels / frame at hand on the iphone 4 than the ipad but really only slightly more. its still only 1/4 of the 3GS)
No, all of that is false.
dpi is unimportant when dealing with graphics on a display. If you actually care about how big the graphics will be in physical space, then use 326 dpi, but it’s hardly relevant in 3D unless you’re talking about a GUI.
No you 
Dealing with the DPI is very important when working an image (especially a UI) : Every screen is 72 DPI based, so if you work with anything else than 72 dpi, you will have incorrect pixel ratio (means that 1 pixel on your work won’t be equal to 1 pixel on your target screen).
I see what you’re talking about (real world size of the artwork), but unless you have the perfect ratio between your screen size and its pixel resolution, you will never be able to reach the absolute “real world size” with DPI. Plus, it would assume that your target screen is perfect ratio too.
To make it short :
- For 1 real world unit, 72 dpi = 1 pixel.
- For 1 real world unit, 144 dpi = 2 pixels.
But in the end, any screen will rescale your picture to 72 dpi.
Which means that if you worked a supposedly 960 x 640 picture on 326 dpi, it will appear as 4347 x 2898 on your iPhone.
Unless you were talking about working on 326 dpi and then export it to 72 dpi, but that would cause the problem I was talking about with the “pixel absolute control” stuff.
More simply, just try it out on Photoshop, by setting different DPI in picture properties. 
DPI is actually used in printing (ads, magazines, etc), as the output base unit is effectively the real world size (inches, cms). But screens output base unit is pixels, which have absolutely no universal size.
Don’t let yourself get lost by Apple’s marketing misdirecting words ^^
n0mad, I don’t know where you got this information, but it’s complicated nonsense.
http://www.cyber-aspect.com/features/feature_article~art~108.htm
never ever - dpi of graphics is only relevant for print and when placing the picture into applications like quark Xpress. Only the number of pixels you set are relevant 320x480 will always be 320x480 even at 1 dpi.
Thanks lots.
Will go with the 72 dpi.
But i have a nagging screen res question still.
Are developers making one HD version of a game to target BOTH the 4G series AND the ipad? I suppose that this 1 game has detection settings to change screen ratios for the 2 different devices?
Or
Are you guys making 1 iPhone/touch game with detection settings for 4g hires textures and a separate iPad version with different 1024 screen ratio.
fewfff… hope that made sense.
Chris
- yes DPI is only used for print, that’s exactly what I said earlier, buddy
- Quark Xpress is a print exclusive software, which is why it will always rescale your view to your pixels. Photoshop does the opposite, it rescales to your dpi.
You are talking about working space here, not exported format. There is a huge difference. - DPI of your work area is relevant of your exported picture size.
As I demonstrated earlier, it will scale you number of pixels on a 72 base unit.
Come on just try it with Photoshop
@Jessy : your links are referencing to real world, universal size (scanning and screen inch size). I’ll let you refer to my previous post about real size not being relevant to computer graphics.
- use variable DPI + real world units when you’re targetting at a picture using inch/cm system.
- use 72 DPI + pixels when you’re targetting computer graphics.
Please guys don’t be so affirmative in denial.
I don’t have the time to provide web links, just try to export the same PSD to JPG in Photoshop, but with different DPIs, you’ll see.
@deadbug : It’s up to every dev’s choice. For my part, I’m working on HD textures, downsizing their exports for smaller res.
@Eric : About screen density, you’re talking about real world size, sir.
Real world size != pixel to dpi ratio (well actually it is, but for a different target platform, like paper)
Deadbug was asking about what dpi to use in his working space, for recall.
Whoever tells him he can take whatever DPI he wants exposes him to take Apple’s reference of 326 dpi. And that would lead to a catastrophic exported size, which was my whole point.
edit : I think we’re just misunderstanding ourselves, as we’re talking about the same reality. So whatever anyway.
Oh and you should have seen that
is incorrect, it’s 4 pixels.
This is simply flat-out untrue. Pixel density of monitors varies a lot, and in fact I think 72 dpi is quite uncommon these days. That’s pretty old, as in '80s/'90s-level tech. Moreover, it’s irrelevant anyway. The only thing that matters is the number of pixels. 960x640 is always 960x640 regardless of whether your display is 72 dpi, 100 dpi, 300 dpi or anything else. The only time you’d care about dpi is if you’re making images intended for print.
There’s nothing misdirecting about the fact that the iPhone 4’s screen is 960x640 pixels at 326 dpi. That’s just hard reality. The only possible misdirection is the stuff about “limit of human perception” that’s bandied about. I can easily see the pixels at 300dpi, at least in regards to B&W print, at a typical viewing distance. The old 300dpi laser printers were quite jaggy for example. It wasn’t until they moved up to 600dpi that I could say they reached the human perception limit thing.
Just make it 960x640. The dpi is totally irrelevant; the only thing you care about is the number of pixels.
–Eric
Ok, I found what misunderstanding were leading us :
- you’re talking about DPI
- I’m talking about PPI
But considering iphone gaming is not yet targetted at paper platform, I think my PPI explanation was right 
In most image editors, this is not clearly said DPI or PPI, but pixels / inch. For someone who doesn’t know the difference, it might be very confusing and lead to enter Apple’s 326 value.
(sorry for the D swap)
It doesn’t make any difference, sorry. When it comes to displays, ppi and dpi are used interchangeably. (In print, dpi and ppi mean two distinct things, because you typically need a number of dots to print a single color pixel.) Things like this:
are just not true in any conceivable sense.
Under no circumstances will you get “catastrophic” exported size as long as you keep your image at 960x480. As VIC20 said:
The only thing that matters here are the pixels. The screen of the iPhone 4 is 960x480 pixels, so that’s what you need to use, regardless of ppi settings. You have 960 pixels across in a screen that’s a hair under 3 inches wide, hence 960/3 = 320 dots (pixels) per inch.
Anyway, at least that makes anti-aliasing, or the lack thereof, less relevant…
–Eric
Well I won’t argue much more because it’s useless now, but please can you just do one thing :
- open any imaging software
- create a new 400 x 400 x 72ppi image
- write a text into it
- now on the fly, change the ppi to 200ppi
- tell me how many pixels the image is telling you it got now
That’s my whole point.
When you export it, some softwares propose you to change the dpi on the fly, without warning you explicitly about the pixel total size change.
An unaware user will therefore export it to an uncorrect size.
You can’t be an “unaware user” if you’re making video games. You need to know enough to uncheck “Resample Image”. It’s really not very hard! It even eliminates a whole bunch of choices for you, preventing user error!
That said, I can’t think of a reason you’d be changing this setting anyway, considering its uselessness.
Yup I understand, but we never know how unaware other users are 
lol, anyway I learned not to confuse PPI and DPI ever, today
The same as before, because I didn’t resize the image.
You’d have to be really unaware to not notice you were resizing 960x640 to something else.
–Eric
System overload. LastWordFighting() application memory overflow.
I agree that dpi is irrelevant here. When working on graphics for display on a screen I never deal with DPI. It’s irrelevant as long as you’re working with sizes in pixels. 1 pixel = 1 pixel.
Sure, if you say "my image is 33,87x22,58 cm, then you have to set your dpi to 72 to get 960x640. But if you set the pixels the image to 960x640 pixels, you should be fine.
I don’t even think png’s of jpegs store dpi information - it’s just the actual pixel dimesions.
(Now, if you work with scanned images or something you do have to make sure the resolution is high enough off course)
i wouldn’t be surprised if apple had their own definition of a pixel, making all your statements wrong!!11!
Retinizzle?