CockersOnline Forum

Off Topic => Photography => Topic started by: JaspersMum on August 15, 2007, 03:50:03 PM

Title: Photograph dpi sizes
Post by: JaspersMum on August 15, 2007, 03:50:03 PM
I have a couple of photos that I want to enter into a photo competition but the rules state they should be 300dpi.

One of the photos is 2930 x 1954 and the other 1805 x 2303 so how do I know the dpi or change it?
Title: Re: Photograph dpi sizes
Post by: Aearoniel on August 15, 2007, 03:53:17 PM
The dpi is the resolution of the image when printed, so both those sizes could still have a resolution of 300dpi. Do you have to print the image to enter it? Otherwise you could play around with resolution in your imaging software.
Title: Re: Photograph dpi sizes
Post by: JaspersMum on August 15, 2007, 04:10:22 PM
The dpi is the resolution of the image when printed, so both those sizes could still have a resolution of 300dpi. Do you have to print the image to enter it? Otherwise you could play around with resolution in your imaging software.

No, it says you can submit on a disc which is what threw me as I did a bit of research this morning and it all pointed to the print size  - wondered if I had missed something  :huh:
Title: Re: Photograph dpi sizes
Post by: Pammy on August 15, 2007, 04:40:36 PM
I think it's for when they print them. dpi is normally used in relation to printing ;)
Title: Re: Photograph dpi sizes
Post by: Helen on August 15, 2007, 08:22:17 PM
your pic is probably 72dpi (is the norm from a canon 400d or 350d which i assume is what you're using?) you will need to get into a programme like photoshop to change the image size.

now if you change it to 300dpi you will consequently increase the image size so that will need to be reduced.

I get images of 2930 x 1954 as pretty much standard on my 400d, and they are always 72 dpi.

Title: Re: Photograph dpi sizes
Post by: JaspersMum on August 15, 2007, 10:23:15 PM
your pic is probably 72dpi (is the norm from a canon 400d or 350d which i assume is what you're using?) you will need to get into a programme like photoshop to change the image size.

now if you change it to 300dpi you will consequently increase the image size so that will need to be reduced.

I get images of 2930 x 1954 as pretty much standard on my 400d, and they are always 72 dpi.


Yes you are correct and they are on the 350.  :D

Do I need to have taken the photos in RAW mode to alter the Dpi though?

If so that restricts the number of photos per card and reduces the number in the continuous shoot, both of which might be compromise worth taking if knowing it was going to be for competition or publication but not sure when basically they are "snaps"  :-\
Title: Re: Photograph dpi sizes
Post by: Helen on August 15, 2007, 10:26:51 PM
nope, it would be easier in raw but you can do on jpg
Title: Re: Photograph dpi sizes
Post by: Pammy on August 15, 2007, 10:33:16 PM
Don't confuse dpi with resolution ;), often displayed as pixels. 72 pixels is the normal screen resolution. However, the terms can sometimes be interchanged.

Wikepedia explain it well here:

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

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

To get the best image both on screen and paper you need to set your camera to the highes resolution. Low resolution will always give lower quality images that limit how big you can make them.

If storage on a card is a problem, buy more or bigger cards ;)
Title: Re: Photograph dpi sizes
Post by: JaspersMum on August 15, 2007, 10:50:16 PM
Thank you all - it's for the Kennel Club competition and we wondered if they might have mixed up, it says

Entries must be submitted as either mounted transparencies, prints or on a CD, and
must have been taken within the two years immediately prior to the competition
closing date. Images must be supplied at 300dpi. If printed on a home printer, the
quality must be of a high standard.


I've put them onto disc and hope they are right, if not, I'm tired and almost don't care now..... I'll go through those links again though before I put in the post.  ::)

Title: Re: Photograph dpi sizes
Post by: Colin on August 17, 2007, 05:19:43 PM

If you use Irfanview you can change the DPI size really easily - open up a photo in Irfanview, click on 'Image', then 'Information', enter new DPI, click 'Change' then 'OK'.
Title: Re: Photograph dpi sizes
Post by: JaspersMum on August 17, 2007, 07:31:21 PM

If you use Irfanview you can change the DPI size really easily - open up a photo in Irfanview, click on 'Image', then 'Information', enter new DPI, click 'Change' then 'OK'.

Thank you Colin and welcome back - it's been a while since you posted!