Comment 1: I received an e-mail from Ken Cooke offering an explanation of how to figure out what resolution your digital images are.

Question 1: Are there any other groups that do have their volunteers photo-document their sites, and if so, how do you organize your photos?

Comment 1

Date: Thu, 26 Aug 2004 20:45:02 -0700
From: Eleanor Ely
Subject: [volmonitor] more on DPI, digital photos, etc.

Dear listserv:

I received an e-mail from Ken Cooke (of Kentucky Water Watch) offering a more complete explanation of how to figure out what resolution your digital images are. Basically, you take the image resolution in pixels and divide it by the desired DPI to see what the final size will be at the desired DPI. For example, in the case of the newsletter, the desired DPI is 300 so I would divide by 300. For example, suppose someone sends me an image with dimensions 2260 by 1620 (in pixels). Dividing by 300, I get approximately 7.5 by 5.4 (this represents the dimensions in inches). Since most photos in the newsletter are printed considerably smaller than that, I know that this photo will be fine.

Until I heard from Ken, I didn’t know about this formula so I was using my “Windows Fax and Photo Viewer” program to essentially do the math for me. I would click on the “edit” icon, look under “file,” click on “properties,” and get a dialog box showing DPI, pixels, and image dimensions. When I typed in the desired DPI (300), the image dimensions would automatically change. Now that I know about dividing the number of pixels by 300, I can avoid all these steps.

For those who may be interested in delving further into this issue, here are some excerpts from Ken’s e-mail:

“DPI and native resolution are two different settings.

DPI is generally a printer setting only.

You can have a 300 dpi image that’s 320 X 240 pixels
You can have a 300 dpi image that’s 6000 X 2000 pixels

The first would print about 1 inch x .8 inch. The second would print about 20 inches x 7 inches at 300 DPI.

When going to print, the main calculation you need to do is divide the image resolution in pixels by the print resolution you want in DPI to see if it will be good enough for the size image you want in your publication.

The human eye can’t diferentiate much beyond 200-300 dpi. Finer printing resolutions than that help with color definition, but not much more. National Geographic is printed at a whopping 2400 dpi!

One thing about capturing images out of a PDF file you should know:

When you convert a print publication to PDF out of a layout and design software such as Pagemaker, the PDF distiller converts the image to a jpeg at the DPI you set in your pinter preferences based on the size it is in your publication. If you have a 6000 X 4000 pixel image but squeeze it down to a three inch by two inch image in your publication, then convert it to PDF at 300 dpi (the default), the conversion will downsample the image to 900 X 600 pixels. So when you grab it out of powerpoint, that is the resolution you get.”
Hope this is helpful!


Eleanor Ely
Editor, The Volunteer Monitor Newsletter
50 Benton Avenue
San Francisco, CA 94112

Question 1

Date: Wed, 25 Jul 2007 00:03:25 +0000
From: Ingrid Harrald

I currently coordinate a small group of water quality monitoring volunteers. Our protocols require our volunteers to photo-document their site (both upstream and downstream). We have yet to find an efficient way to organize and store our photos. Are there any other groups that do this, and if so, how do you organize your photos?

Thanks for your help!


Responses to Question 1

Date: Tue, 24 Jul 2007 22:15:04 -0400
From: Eric Eckl


You should check out an online photo service called Flickr:

What’s really great about Flickr is you can assign multiple tags to each photo, such as: Pennsylvania, Susquehanna, Fishing, 2006, children, etc…

Then you can search your collection by keyword. Once you get the hang of it, it’s a big improvement over putting your pictures into folders.

Free Flickr accounts are free. Pro Flickr accounts are cheap.

Good luck with your search.

Eric Eckl
Water Words That Work
P.O. Box 2182
Falls Church, VA 22042-2182
(703) 822-4265
Cell: (703) 635-4380


Wed, 25 Jul 2007 12:04:57 -0400
From: Carolyn Sibner

Hi Ingrid, is another online photo service that is also free and well organized. You can also have it print out your photos with captions on the back, at no extra cost, so you don’t have to write on the date and location by hand.
I also downloaded their software for free and use it to organize and fix my photos on my computer.

Hope this helps,


Date: Wed, 25 Jul 2007 17:00:12 -0700
From: ED

Another way to go, if you maintain a website is to install free software called Coppermine.
It is a great way to store and share your photos and key word searches are included.

Mondy Lariz, Executive Director
Stevens & Permanente Creeks
Watershed Council
2353 Venndale Ave
San Jose, CA 95124
(408) 356-8258


Date: Wed, 25 Jul 2007 20:35:20 -0400
From: Eric Eckl

Well, another advantage of Flickr (Disclosure: I’m a HUGE fan) is that a lot
of users have elected to share their photos for others to use.

Then you can start entering terms in the search box. If you like a photo,
you can use it according to whatever terms the photographer stipulates. So
Flickr is a great place to both keep the photos you took, and to find the
photos you wish you had taken.

For example, I put a post on my blog today that mentioned a rain garden. I
don’t have a picture of a rain garden, but I found one on Flickr in about
two minutes. The photographer stipulated that others are free to use the
photo so long as they credit her. So I used the photo and credited her. Just
mouse over the photo to see the credit.

Eric Eckl
Water Words That Work
P.O. Box 2182
Falls Church, VA 22042-2182
(703) 822-4265
Cell: (703) 635-4380

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