PREPARING AN IMAGE, IN PHOTOSHOP, FOR PROJECTION ONTO A
LARGE SCREEN
Actions are in red:
FACTS YOU NEED TO KNOW FIRST:
- For projection purposes in club, interclub & inter-federation competitions;
national and international salons, the images are usually projected in
the sRGB colour space. Ensure that your images are created and saved in
this colour space as they will look quite different when they are converted
(automatically) by the projector for projection purposes. To check your
colour space, in Photoshop, go to edit/colour settings/. Then, in the
diaogue box leave most at the default but check that the Colour space/
RGB has sRGB IEC 61966-2.1 identified in the drop-down options. Also,
tick the box 'ask when opening' for profile mismatches. This will warn
you when, or if, you open a file that hasn't been created or saved as
sRGB.
- Open the image file in Photoshop.
- Go to: Image/Image size. This opens
a dialogue box which shows the size of your image files (1) in pixels
ie., the amount of information that is saved (2) the physical dimensions
of the image at any specific resolution.
- The bottom third of the box has 3 check boxes. (i) 'scale styles' which is only effective when you have a layer with effects active (ii) 'constrain proportions' should always be checked if you don't want your image distorted (iii) 'resample image' should be 'bicubic' and will be checked or unchecked as needed.
- If 're-sample' image is checked then all the options to add or throw away pixels (image information) are active. If the box is not checked then the 'pixel dimensions' boxes are not active and, in whatever way you alter the resolution or physical size, you will not be discarding vital image information. The 3 boxes will be linked and, as you change one, then the others will alter to re-distribute the information stored in your pixels.
- The more pixels you have then the greater the size of the print you can make. If your 're-sample image' box is checked then you can add pixels; this is called interpolation. However, this is achieved by Photoshop sampling the existing pixels and 'inventing' pixels of the colour that it thinks 'fits' best. (putting it in definitely 'non-technical' terms!) If large numbers are interpolated this can lead to 'fuzziness' and a general degradation in the quality. Sharp and detailed pictures will suffer most quickly. You can also throw away pixels but, once they have gone, they've gone and there's no getting them back.
- If the file is for printing then try to avoid interpolation and re-distribute the pixels balancing physical size against resolution. Make sure the 're-sample' box is not checked, so that the pixels are unaffected. If it is going to a magazine you will probably be asked for a file at 300ppi (pixels per inch) For your own purposes, experiment! 240ppi is a happy compromise; with some prints you might get away with a lower number, perhaps 180ppi.
- If the file is for projection then you will almost certainly have to discard pixels so save the original file as a psd and save the file intended for projection as a new one.
- Images for projection are required to be either 1400 pixels wide by 1050 pixels high or 1024 pixels wide by 768 pixels high. The size is determined by the projector to be used. Depending on how it is set it will re-size your image either down or up; neither of which is particularly good for quality. If the file is small it might be projected as a small image and not fill the screen; again, not showing your image to its best advantage.
- In many instances, if a smaller image file is projected, it will display against a black background but this isn't always the case; again, it depends upon how the projector has been set up.
SIZING THE IMAGE (this method will put a white key-line around the picture to 'lift' it from the black background) Using this method you will increase the canvas (or background) space around your image. It will fill the projection area completely.
These are instructions for 1400pix X 1050pix.
- Flatten the file if you have layers open. (Your layer will then show as 'background' in the layers palette)
- Go to Image/image size to open the
dialogue box.
Check the 're-sample image box'
Check the 'constrain proportions' box.
'Resample image' should be bicubic.
Look at the pixel dimensions.
Your file might fit perfectly but it's quite likely to need some space 'filling in'.
- If it's essentially a landscape format try the width, first and change the pixel value to 1394. Look at the height and make sure it's not greater than 1044pix. If it is, then lower the pixel value in the height box to 1044 and accept what the width becomes.
- If it's essentially a portrait format then try the height first and change the pixel value to 1044 and accept the width (which will be a lot less than 1400)
- If it's more square format then juggle the two dimensions until one is correct and the other under the maximum number.
- You can ignore the document size boxes. They will have no effect at all on how it is projected.
- When these are satifactory, click OK
- Make white your backgound colour in the tool box
- Go to Image/canvas size. This opens
up a dialogue box.
The box shows the 'current size' (information) and 'new size' with active options. It also show a 3 X 3 box with an active middle square, which represents your image. This allows you to determine where you want the extra canvas to be added, and can be dragged up, down or sideways. For our purposes, here, leave it in the centre.
The box has a 'canvas extension color' option box at the bottom. Make sure 'background' is selected.
- Use the options boxes in width and height to select pixels.
- Add 4 pixels to each value (the
values in 'current size' will not alter at this stage) and click
OK.
This action has placed a 2pixel-wide white key line all round your image,
- Make black your background colour in the tool box.
- Return to Image/canvas size. Make pixels your option again.
- Add the necessary number of pixels to make
the width 1400 and the height 1050. Click OK
You will now see your image on screen against a black background. If you increase the magnification to 100% you will see the narrow white key line that just 'lifts' it.
- Save this file as a jpeg of highest quality.
This the the more usual file format required.
Sometimes the option to enter the image as an uncompressed TIFF file is offered. If you decide to use this option ensure that all layers in your image have been flattened.
If you have a 1400pix X 1050 pix file ready for projection, but you need a 1024 X 768 file then:
- Go to Image/image size.
- Check the 'resample box' and the 'constrain proportions' box.
- Change the width from 1400 pixels to 1024 and the 1500 will automatically change to 768. Click OK
- Save as another file (you may need the larger one again!)