resolution

[justfly]

I am very unexperienced in digital photos. My camera is a Canon G5 and I see that all photos I take get with 72 dpi, it doesn't metter how high the resolution and compression the camera is adjusted to take a photo. I see that the sizes of the photos are different although all of them have 72 dpi. What should I do to have a good quality photo with 300 dpi?? Thanks from Brazil.

[Roger_Cavanagh]

The DPI doesn't make any difference to the quality of the picture, just the size it comes out of the printer.

I explain more here:

http://www.pixelpixel.org/pstips/01.htm

Regards,

[The Photo Tuell]

justfly wrote:What should I do to have a good quality photo with 300 dpi??

Not another DPI addict...

You don't need 300 DPI to get a good quality print!

DPI is overrated. Try doing some prints straight from the camera (cropping only) and you'll probably be pleasantly surprised. I've done award winning 20"x30" prints from my G2, with no interpolation.

Just crop your pictures to the right ratio (of pixels), don't worry about the DPI.

[Jesper]

Understanding Resolution
http://www.luminous-landscape.com/tutorials/understanding-series/und_resolution.shtml

The only thing that matters with a digital photo is the size in pixels (width x height). How many dots or pixels per inch there are, depends on how large you print it.

If you print a photo of 2272 x 1704 pixels (the largest size available on the G3) at 10 by 7.5 inches, you will have 2272 / 10 = 227.2 DPI, it's as simple as that.

The DPI number that is stored in your JPG file is only a "hint" and it doesn't mean anything with regard to the resolution of the photo.

[JMSetzler]

72 dpi is standard screen resolution and yes, you do need more than that to get a good print. When you see 72 dpi, you also probably see that the image dimensions in inches are 20x30 or something like that. In photoshop, turn off the bicubic resampling and change the dimensions to something closer to the actual print size you are looking for. After you do this, your dpi will show the actual dpi for the print size you wish to achieve.

I wrote a tutorial recently on creating print files that can be viewed here:

http://www.dpchallenge.com/tutorial.php?TUTORIAL_ID=10

Cheers and good luck :)

[justfly]

I have been learning a lot with all of you. Thanks!!!

To be more specific, I was asked to send a photo for an article with the following details:
"high-res digital image files. However, high-res digital image files are only accepted with following technical specifications:"

* EPS or TIFF file
* 300 dpi resolution
* CMYK color separation
* min. size 4 x 6 cm, max. size 13 x 18 cm

As it is urgent, please, explain me something about saving the photo in eps or tiff file and CMYK color separation.

Thanks again.

[w10d]

justfly wrote:
* EPS or TIFF file
* 300 dpi resolution
* CMYK color separation
* min. size 4 x 6 cm, max. size 13 x 18 cm

As it is urgent, please, explain me something about saving the photo in eps or tiff file and CMYK color separation.

Thanks again.


I take it you have understood the dimesions/resolution relationship. TIFF file format will probably be the best option for you - in your software select 'save as' and select TIFF as the file format. You may get further options, depending on your software, LZW compression will make the file smaller, without harming the image; it is sometimes unpopular as it can slow down opening files - not much of an issue with computers thesedays. Confusingly, JPEG compression is now available within the TIFF format (at least in PS - TIFF is actually an Adobe format), it is still a lossy compession routine, probably best avoided in this case.

You will need more info regarding the press to hope to obtain the best conversion to CMYK - I'm surprised they have asked you to do this. I would suggest you either find out exactly what their requirements are, or see if they will accept RGB for seperation by their repro.