Preparing Images for Projection

Preparing Images for Projection

Images for projection need to be resized and presented in the correct colour space.  The operation is fairly straightforward.  Here’s how to go about it.

If your image is a Tiff or a PSD file and you have layers in place, firstly flatten your image (Layers – Flatten Image.  This will not be necessary if your image is a JPEG file.

Projected images look attractive on the screen when framed by a very narrow key line.  Go to Select and choose All.  This will set the “marching ants” in action around the perimeter of your image.  Now go to Edit and choose Stroke.   Change the colour to white by clicking the “Color” patch this will invoke the Colour Palette, click on a white area and then OK.  In this sample the width is set at 3 pixels but this will vary according to the size of your image.  A little trial and error will soon give you an idea of a suitable width.  Note that the location must be set for Inside otherwise the keyline will either be only half the width you have chosen or not visible at all.  Once Inside has been chosen the Stroke dialogue will default to this every time you use it.  Leave the Blending at it’s default setting as illustrated here.

The keyline should not be too wide as a broad white line around your image will be distracting.  Of course, it is possible to have your line any colour you wish but be very careful as a bad choice will also be detrimental to the appearance of your image.  When done go to Select – Deselect to remove the marching ants.

Press F on your keyboard three times and Photoshop will display your picture against a black background so that your keyline will appear as it will when projected.

See the illustration below.

Pretty neat !

Now you need to resize your image to make sure that it will fit the screen when projected.

Go to Image – Image Size to bring up the dialogue box.

Untick the Resample box and alter the Resolution to 100 or 200 Pixels per Inch (PPI).  This figure is not set in stone but must not be less than 72 ppi or quality will suffer.  Larger than 200 just uses up valuable storage space.  Some outside exhibitions will demand that you use a set size so always check this on the entry sheet.  Now retick the Resample box and this will bring alive the Pixel Dimensions boxes in the top of the Image size box.  At the same time make sure that Bicubic or Automatic is set in the lower part of the dialogue. Constrain Proportions must also be ticked.




The box will now appear something like the above illustration.  Make sure that the Document Size box is displaying Inches and the Pixel Dimensions boxes are showing Pixels not Percentages.

Now for the important bit !  Your Landscape (horizontal) shaped image must not exceed 1600 x 1200 pixels; any size above this will not appear on the projector screen.  You will see that the boxes are linked so that altering the width automatically adjusts the height to avoid distortion.  If you type in 1600 ppi as your width and find that the height exceeds 1200 ppi then  simply type 1200 in the height box and leave the width to sort itself out.  For a Portrait (vertical) shaped image the height is the important figure as this must not exceed 1200 so set this and the width will automatically be OK. Click OK when done.  The image will now shrink on the screen – don’t panic – it’s fine.  To prove it press  Ctrl and Zero on your keyboard and the image will zoom up to it’s former, monitor filling glory!

Please do take note that with improvements in technology some exhibitors may require different pixel dimensions.  Always check the requirements on the entry forms.

The next step is to check that your image is in a suitable “Colour Space” for projection.  Projectors use the sRGB space.  Go to Edit – Convert to Profile and if necessary convert your image to sRGB by ensuring that the Destination Space reads “ sRGB etc” as shown in the next illustration. The conversion options should be left at their defaults as shown.  Click OK when this is done.  Your image will not appear to have changed but when projected an incorrect setting such as Adobe RGB will result in poor colour on the screen.  See the next illustration.

All that is left to do now is to save your image as a JPEG file.  Go to file and the Save As.  Choose where you wish to store the image and from the dropdown menu choose JPEG and click Save.

The following box appears –

Move the slider to the extreme right to ensure maximum quality and click OK.  You can see in this box that the file size of our sample image has been reduced to a mere 735.9k but the amazing fact is that on the six foot screen you will not notice!

To further prepare you images for projection in our club you will need to rename them, for detailed instruction on how this is done please go to the upload page HERE

Article Author: Len Harris
©Copyright Kidderminster Camera Club 2010.   Updated August 2021