40D resolution (DPI)

[opticals]

when you transfer your photos to your computer and open it with photoshop, what's the image size you get?
I've go the correct pixel size but resolution only 72 DPI?
Is it suppose to like that?
My old 10D read 180 DPI..

[boredphuck]

i got 72 as well. forgot to ask hw to do it in 300dpi for printing purposes? but then with the resolution, 72 seems to be sufficient.

[di0nysus]

you can set the dpi under 'image', 'image size'. i wldn't bother about it if you know the maths,

say if u'r printing a 6" by 4", it is good to have 300dpi, hence all you need is 1800 x 1200 in your final image before printing.

Hence you could also try a crop tool, set 6" by 4", then dpi to 300dpi, and crop, you'll get 1800x1200.
else you can also simply crop 1800 x 1200 pixels and dun worry about the dpi.

The printers do not look at the dpi!

[boredphuck]

Originally Posted by di0nysus you can set the dpi under 'image', 'image size'. i wldn't bother about it if you know the maths, say if u'r printing a 6" by 4", it is good to have 300dpi, hence all you need is 1800 x 1200 in your final image before printing. Hence you could also try a crop tool, set 6" by 4", then dpi to 300dpi, and crop, you'll get 1800x1200. else you can also simply crop 1800 x 1200 pixels and dun worry about the dpi. The printers do not look at the dpi!

oic. so 72 is sufficient for printing right?

[m3lv1nh0]

I think you need at least 240 - 300 dpi for printing. 72 dpi is meant for web images.

[Draccoyap]

Originally Posted by di0nysus you can set the dpi under 'image', 'image size'. i wldn't bother about it if you know the maths, say if u'r printing a 6" by 4", it is good to have 300dpi, hence all you need is 1800 x 1200 in your final image before printing. Hence you could also try a crop tool, set 6" by 4", then dpi to 300dpi, and crop, you'll get 1800x1200. else you can also simply crop 1800 x 1200 pixels and dun worry about the dpi. The printers do not look at the dpi!

What I understand is somewhat different. dpi (dot per inches) is mainly for printing while "pixel per inches" is mainly for display, which is the resolution we usually talk about, isn't that? As far as i know, changing the dpi will not affect the resolution.

to me, 72dpi is not enough, if possible, go for the 300dpi.

[opticals]

When I set to Large/fine in the camera.
40D's photo in photoshop read 3*** X 2*** with a 72 DPI.
With my 10D it read 3*** X 2*** with a 180 DPI.

Nikon system is 3*** X 2*** with a 300 DPI.

So the DPI mean anything?
All it all about the pixel count?

[Big Kahuna]

See if this helps

http://en.wikipedia.org/wiki/Dots_per_inch

[boredphuck]

Originally Posted by m3lv1nh0 I think you need at least 240 - 300 dpi for printing. 72 dpi is meant for web images.

yep. thats what i wanted.

[SianZronG]

From my understanding in a computer system it is forever 72 DPI.
So no matter what a pixel is 72 DPI in computer systems. BUT in printing world a print pixel can be much higher res, let's say 300DPI?
So to compensate for that in a computer system we would increase the resolution. There is a technical reason why we need 1800 x 1200 for a high quality 4R print.

a 4R is 4" by 6"
DPI is DOT PER INCH
So for print we have 300 dots per inch
4 x 300 = 1200 PIXELS
6 x 300 = 1800 PIXELS

That is why you get 1800x1200.

So let's say another example if you want to display a 4R size image on the screen it would requre FAR LESS DPI (72)
4 x 72 = 288 pixel
6 x 72 = 432 pixel

A 432 x 288 image will turn up around 4R size on screen with 100% zoom. =P

Hope this helps.

[boredphuck]

thanks. so what size is needed for a A4 page?

[SianZronG]

Originally Posted by boredphuck thanks. so what size is needed for a A4 page?

A4 = 210mm x 297mm

210mm = 8.267716535442"
297mm = 11.6929133858394"

A4 roughly translates to about 8.3" x 11.7"
For Print DPI of 300
8.3" x 300 = 2490 pixels
11.7" x 300 = 3510 pixels

So a A4 print need 3510 x 2490 for a high quality print!

Cheers~

[boredphuck]

Originally Posted by SianZronG A4 = 210mm x 297mm 210mm = 8.267716535442" 297mm = 11.6929133858394" A4 roughly translates to about 8.3" x 11.7" For Print DPI of 300 8.3" x 300 = 2490 pixels 11.7" x 300 = 3510 pixels So a A4 print need 3510 x 2490 for a high quality print! Cheers~

thanks again. i am terrible in maths. need the specs for the cover of my sales kit.

[Draccoyap]

Originally Posted by SianZronG A4 = 210mm x 297mm 210mm = 8.267716535442" 297mm = 11.6929133858394" A4 roughly translates to about 8.3" x 11.7" For Print DPI of 300 8.3" x 300 = 2490 pixels 11.7" x 300 = 3510 pixels So a A4 print need 3510 x 2490 for a high quality print! Cheers~

i think the units are wrong. DPI is dot per inches, and when you are calculating pixels, you are talking about PPI, pixel per inches. when you time 8.3 inch with 300DPI, you will get 2490 dots, not pixels.

for the same resolution, you may still have either 300DPI or 72DPI, which gives you different printing quality.

See short article here:
http://www.deedoos-digital-scrapbook...esolution.html

To me, don't have to think so much, the 300DPI is always good if you can have that.

[JLee]

300dpi is the industry standard for printing, while 72dpi is good enough for viewing in your computer/web. DPI and PPI are two very different thing. Google for more info, if you're really into this.

[rinaldi86]

erm... 72 or 300 is not a cause of concern actually..

don't worry... last time i used to get worried a lot about the res...

but after printing 12"x18" at photo lab, I'm pretty much convinced that the 72dpi "only" is very sufficient for even a large print out!

shown it to my friends who are quite anal on resolution & print quality and they mentioned too, that the print out is excellent

[SolBadGuy]

Originally Posted by rinaldi86 erm... 72 or 300 is not a cause of concern actually.. don't worry... last time i used to get worried a lot about the res... but after printing 12"x18" at photo lab, I'm pretty much convinced that the 72dpi "only" is very sufficient for even a large print out! shown it to my friends who are quite anal on resolution & print quality and they mentioned too, that the print out is excellent

hmm.. sorry bout the OT, where do u print? did they use any plugin or anything to interpolate ur image?

[rinaldi86]

Originally Posted by SolBadGuy hmm.. sorry bout the OT, where do u print? did they use any plugin or anything to interpolate ur image?

KTDI (Kim Tian Digital Imaging) @ Chinatown..

Nope.. did request them not to do any corrections on the image

[SolBadGuy]

Originally Posted by rinaldi86 KTDI (Kim Tian Digital Imaging) @ Chinatown.. Nope.. did request them not to do any corrections on the image

ahhh... ok... hmm.. will prob try printing thr with 2 identical images, one with 72DPI n the other with 300DPI to compare side by side

have never printed thr before. in fact havent printed any photos for the last few months. some of my frens did recommend me to print thr. will get my lazy bum thr some time soon..

[Clockunder]

Similar questions like this have been asked many times previously in Clubsnap in various sub-forums.

Do a search and you will get some good answers.

If you're sending the pictures to photo labs to develop, the only thing that matters is the picture’s own resolution (i.e. no. of pixels X by Y) and the DPI doesn’t matter.

You will get the same image regardless of what DPI (72 or 300 or whatever) is embedded in the picture as long as the pixel resolution is the same.

For e.g. if you submit a picture @1200x1800 resolution with 72 DPI embedded and another same 1200x1800 picture with 300 DPI embedded, you will get exactly the same image quality. This is because the printing process does not make use of the DPI info at all.

For small prints like 4R (4" x 6"), the recommended resolution to be submitted is 300 pixels per inch meaning that at least :

4 x 300 = 1200
6 x 300 = 1800.

So 1200x1800, 1600x2400, 2000x3000 or even odd numbers like 1212x1818 or 1460x2190 is also fine as long as there is at least 1200x1800 pixels and the aspect ratio matches the print.

300 PPI is the recommended resolution based on the ability of a normal human eyes to resolve details in the printed picture size at the normal viewing distance for a picture of this size.

Usually, 240-300 PPI is fine for small prints like 4R. Of course, no one can stop you from using lower than this if you insist.

For larger prints such as S8R (8" x 12"), the recommended resolution is 150 PPI. It's lower because the bigger picture is expected to be viewed at a greater distance away than a 4R picture.

The larger the print, the lower the recommended PPI because the picture is expected to be admired at greater distances. (You don't don't see people using 300 PPI for billboards, do you?).

So, if you're printing as large as 16" x 24", even a 75 PPI may suffice.

If 300 PPI is used for a 16" x 24" print, the required resolution would be a mind boggling :
16 x 300 = 4800
24 x 300 = 7200
= 34.56m pixels which is attainable by larger format cameras.

===========================

So you might ask what the DPI embedded in the picture is for. If you’re using printing with your own home printing machine (such as Epson, HP, Cannon etc.) through software like Photoshop, your printing machine may be set to use the DPI embedded in the picture as if it is PPI to determine the print size. So if your picture is 1200 x 1800, your picture printed would turn out to be :
If DPI is 300.........4” x 6”
If DPI is 150.........8”x 12”
If DPI is 75...........16” x 24”


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Technically, DPI refers to Dots per inch and the printing process uses a few C/M/Y/K/B dots to give the apparent colour of each pixel printed. So you see 2400 DPI etc. specifications for home printers. However, DPI and PPI are often (mis)used interchangeably to refer to the same thing ……..pixels per inch and this has become a norm.