Photochrome Camera Club

Executive Summary

To submit photos for projection at a club meeting please email them to photochromeprojectionist@gmail.com by midnight of  the Wednesday before the meeting.

Submitted pictures must be in jpeg format with a maximum long side dimension of 1024 pixels.

Name your image files: <Category>-<Photographer;s Name>-<Title>.jpg

Categories are:

• Pic2 – up to 2 images taken on Field Trips or special evenings
• TN – Theme Night, two images for each Theme
• OP – Open Pictorial, two images
• JN – Judging Night, two images

Detailed Explanation:

Submitting Images to Photochrome for Digital Projection

Let us consider the physical dimensions of the image to begin with. We ask that when you submit your images for projection that you resize your image so that the longest side is 1024 pixels.  Why 1024 pixels? Because that is the native resolution of the projector.  If your image is not resized to take advantage of this characteristic of the projector your images will not look their best.  If your image is too small the projectionist has to decide if they should show your image small with a border around it or if they should stretch the image to fill the frame.  If your image is too big the projectionist can opt to shrink the image to the projector frame but it will not look as good as had you submitted the image at the correct resolution to begin with.

Why is this? If your image is too small and we are stretching it to fill the frame, the computer has to ‘guess’ at what to add to the image to make the picture look bigger.  If your image is too large, the computer has to decide which lines to discard to shrink the image.  Neither of these processes is optimal for your image’s fidelity.

So, how do you resize your image to send it to us? All the programs I have used (PhotoShop, PhotoShop Elements, Gimp, Paintshop) have similar interfaces for achieving this. The menu option you use will be something like Image > Resize > Image Size. The only thing you have to make sure of is that you are resizing the image itself and not the canvas upon which the image resides. Usually you will now see a dialog window that shows the image’s current dimensions and allows you to change these dimensions.  The most important thing to remember is that the only thing that matters is pixels; forget about combinations of dimensions in inches and resolution in pixels per inch – this is only important when you are printing your image.  We just want to change the dimensions of our image for the projector (or screen) and these display devices don’t know anything about inches – they only understand pixels.

To resize your image you may have to check a box labeled “resample image” and chose a method to achieve this. I choose Bicubic which is generally accepted as the most accurate and convenient method in this situation. You must also check the “constrain proportions” option; this ensures that your ratio of image height to width is maintained as the image size changes.

Look at the current image size; unless your image is perfectly square one dimension will be larger than the other. Change this larger value to “1024 pixels” – the smaller value should also change at this point (to something around 680 pixels for a DSLR) and you image should now look the same but smaller. If your image happens to be square, it should matter if you change the height or the width as either will have the same result. The next step is optional but I now look at my image at the “actual pixels” zoom level and apply the unsharp mask to an amount appropriate to the subject and the new image size. Sharpening is a subject for a larger article but, to keep a long story short, I sharpen to some extent as the final step before saving every time I resize an image either up or down.

You now want to save your image as a new file name (“save as”); if you just do a blind save there is a danger that you might over write the original file which would be bad. You want to save the image in the jpeg format which means that your new image will have the “.jpg” file extension. The file name itself is assembled thusly:

An example resulting file name would be something like OP-Joe Blow-SF Bay Bridge at night.jpg. The file name may seem long winded but it allows the projectionist to identify everything they need to know about what to do with the submitted image they receive from the file name itself.

When you hit the save button, as you chose the jpeg file format, you will now be asked how much compression you wish to apply to the image – in Adobe products this is a scale from 1 to 12. Up to now we have been dealing with size as it relates to the physical dimensions of the image but compression relates to the byte size of the file. The more compression you apply to an image the smaller the file size you end up with however there is a cost; image fidelity. When compression is applied, image data that probably isn’t important is discarded; the operative word here is ‘probably’. Compression is a mathematical process; the more severe the compression you apply, the more data is discarded and the smaller the resulting file size. When you are sending images to friends and family and you don’t want massive attachments in your emails it is alright to apply strong compression as much as 5 on the the jpeg compression scale but when you are sending images to be seen by other photographers you want to be more conservative – somewhere between 8 and 10 on the compression scale seems appropriate. The problem with severe compression is that the data that is discarded results in what can be seen as compression artifacts. Compression artifacts can sometimes be seen as posterizing in what should be smooth gradients, ‘jaggies’ along sharp edges, mosquito noise or blockiness in busy regions. Once your eye tunes into artifacts they are hard to ignore and can distract a viewer of your images.

Save your prepared image files somewhere you will be easily able to find them like the desktop or your top level images file. Now start your email program or go to the your webmail and attach your files to an email to photochromeprojectionist@gmail.com individually.  Some email programs and services at this point will recognize that your attachments are pictures will offer to ‘optimize’ your images for email delivery; do not allow them to do so as they can ruin all the hard work you just went through to prepare your images for submission. Similarly, some editing programs offer the user the facility to send images via email directly from the tool. Unless they are transparent about what they are doing to the image, especially concerning the physical file size and the amount of compression they will apply to a file, then it is better that you go through the inconvenience of manually resizing your images as described above rather than be disappointed when you see you images projected on the large screen at the club.

I realize that these instructions may seem a little long winded but I hope that by understanding exactly why you should resize your images in a certain way you will save time and effort when you next submit digital images for projection.