problems sizing pics

[galanthus]

Hi guys, I am v v desperate

I've joined a stock site and completely understand the thumbnail-type prints they need, however, I'm having a problem sorting the originals re size They are asking for a dpi of 300, they don't state per inch or per cm so I'm assuming per inch. However, as soon as I do this, my files are coming up as big as w 16200 x H 10800 This is enormous and I fear far too big. Can anyone help me choose what is possibly a fairly standard size for the pics ? I know their different shapes etc, however, a rough idea would be great. Am completely new to the stock site thing any help wld make me happy

[eeyore]

Originally Posted by galanthus

Hi guys, I am v v desperate

I've joined a stock site and completely understand the thumbnail-type prints they need, however, I'm having a problem sorting the originals re size They are asking for a dpi of 300, they don't state per inch or per cm so I'm assuming per inch. However, as soon as I do this, my files are coming up as big as w 16200 x H 10800 This is enormous and I fear far too big. Can anyone help me choose what is possibly a fairly standard size for the pics ? I know their different shapes etc, however, a rough idea would be great. Am completely new to the stock site thing any help wld make me happy

DPI stands for dots per inch so that is the answer to your first question

stock sites expect the files to be large but not quite that large - I would suggest contacting your chosen site and asking what dimensions they prefer then you can set your photo editing software to these dimensions at 300dpi

many stock agencies also specify a minimum file size in megabytes and some require .tiff rather than .jpeg so it is definitely worth checking with them if the info isnt on their website

[galanthus]

Dot per inch Doh !!

thanx eeyore, they've specified a minimum of of 3000 pixels on the longest side, a mimimum of 3000x2000 overall. HOwever, they haven't given a maximum. I realise it's poss to get a request for a specific size and I could then modify the originals in cs2. I suppose I need help with a window of average sized pics for this kind of site. I think you've confirmed that some of the sizes are far too big so that helps. Oh and no meg maximum that I can see and the format is high quality jpeg.

[peterjclarke]

DPI = dots per inch. When you resize an in Photoshop for example you change the DPI to 300 (green circle) then in the width box (red) you type in the size e.g. 29.7cm for A4. It will obvoiusly be larger for an agency. The important bit is the resampling. I guess you are mabe not using Photoshop and whatever software you are using is resampling the image differently. An image library usually wants the full size image from a RAW file so it is best to do this in your RAW converter. My D200 it would be 3872 pixels x 2592 pixels at 300 Dpi or 32.78cm x 21.95 cm at 300Dpi.

If you are interpolating an image to a larger size this should be done using Photoshop's 'bicubic smoother' option. If reducing the size use 'bicubic sharper'.



If you are still not sure how to do this then either PM me or you can give me a call. My number is on my website Outward Vision

[mh68]

Surely the figure of 300dpi is meaningless unless related to a print size
Eg, a 10x8 print at 300 dpi would be 3000px by 2400px, whereas a 6x4 print would be 1800px by 1200px.Both are 300dpi but the actual image size in pixels is dependant on what size its going to be printed at in inches.
If the agency has specified a min image size of 3000x2000 pixels I`d go off that,and if someone asks for an image at 300dpi for a large size print, interpolate the image to the required size upon request as you mentioned.
There is a program called "genuine fractals"(just google it for info) which a lot of pro`s apparently use, which is said to give much better results than Photoshop when upsizing.If you ended up getting plenty of requests for your images it may be worth considering buying a copy.

Mark H

[Paul mabbott]

No dpi is the density/size of pixels - equivalent of grain size on a film camera. The higher the dpi the more detail is captured. Imagine going down to 10 dpi - you would have very poor definition!

Your argument applies to a projected tranparency - increase the size of the image and decrease the definition but it doesn't apply to digital images.

Originally Posted by mh68

Surely the figure of 300dpi is meaningless unless related to a print size
Eg, a 10x8 print at 300 dpi would be 3000px by 2400px, whereas a 6x4 print would be 1800px by 1200px.Both are 300dpi but the actual image size in pixels is dependant on what size its going to be printed at in inches.
If the agency has specified a min image size of 3000x2000 pixels I`d go off that,and if someone asks for an image at 300dpi for a large size print, interpolate the image to the required size upon request as you mentioned.
There is a program called "genuine fractals"(just google it for info) which a lot of pro`s apparently use, which is said to give much better results than Photoshop when upsizing.If you ended up getting plenty of requests for your images it may be worth considering buying a copy.

Mark H

[mh68]

DPI= dots per inch.A term used to define print quality. In the case of digital images dot=pixel, so really PPI (pixels per inch) would be a more accurate term to use,but DPI is the most often used. The DPI setting in relation to a specific digital image size determines what size (in inches) that image will print. Similarly, the DPI in relation to a specific print size(in inches) determines how many pixels on the X and Y axis an image must be to make that resolution.
To resize an image to a specific DPI setting a print size is required.

Mark H

[RichBrew]

300 dpi is the standard for commercial offset printing. All the work I print is at that resolution, although occasionally I see 'low res' images incorporated in layouts (which, incidentally, look dreadful).
Stock agencies require 300dpi so they can supply clients with images that will look sharp on various paper stocks used in the printing industry. Anything above 300 is deemed to be un-necessary, as the human eye has difficulty in resolving any more detail at normal viewing distances.

RichBrew

[jennyb]

Your images come out of the camera at a fixed pixel size (mine are 3888 x 2592 = 10MP). Inches/cm don't mean anything until you come to print them.

If I print them at 300dpi (or ppi as Mark says) the size would be 13" x 8.6".

If I print them at 600dpi the size would be 6.5" x 4.3".

I believe some cameras have different pixel sizes, but taking a simplistic view, I think my logic is correct?

Jenny

[mh68]

I`m not sure about varying pixel sizes between cameras,its not something i`ve seen mentioned anywhere, but the rest is spot on Jenny

Mark H