Once the pictures are added and sorted you choose the duration for them to stay on screen and a transition to get from one slide to the next, such as cross fade, zoom, dissolve and so on. All very simple, so why are the results so frequently disappointing?

The first thing to understand is the difference between slideshows on VCD (bad), SuperVCD (just all right) and DVD (brilliant). To make SVCD or DVD slideshows the authoring program must re-encode the images as MPEG2, the compression format used for DVD. Memories on TV comes in two versions, one with and one without an MPEG2 encoder. Buy the bundle.

The second thing to know is that letting the authoring program resize images will produce dreadful results. The pictures need to be resized in an image editing program to fit television dimensions. Our PAL system has screen dimensions of 576 pixels (lines) high and 720 pixels wide. Images should fit within those dimensions. A widescreen TV is 576 lines by 1024 pixels. These numbers set the maximum size for the image, but it is best to leave a margin for overscanning.

Next, there is a useful little-used feature in Photoshop. When a File/New is opened the dialogue box contains a drop down section labelled Preset. Click on the drop-down arrow and there are presets for both standard and widescreen PAL television format. Click on one and it brings up a new file template in the right dimensions, pixel shape, resolution and colour space for the TV system. Fill that New image with a background colour, pattern or image and then copy and paste the edited picture into that space and a slide has been created. Flatten the layers and save as a JPEG, PNG or TIFF file.

Because monitors and PCs have different pixel shapes Photoshop has a facility for displaying the correct aspect ratio but the image will look degraded with jagged edges. Don’t worry, it won’t look that way on the TV.

The TV is brighter and has a higher contrast than the computer monitor. When an image has been edited in a program like Photoshop so that it looks right on the monitor it will be too bright and contrasty for television. The gamma of a Mac monitor is closer to TV and the adjustment will not need to be so drastic, but for a PC the image needs major adjustment.

It saves money to use re-writable blank discs for the trial and error part of the process. As a starting point in Photoshop, (including Elements), open the Levels dialogue and adjust the slider under the histogram to the right until the centre Input level reads 0.8. This adjusts the image gamma closer to TV standards. It will look too dark on the monitor but it will look different on the telly. Apply this gamma correction to a few images, load them into the authoring program, create a show on a re-writable disc and check it on the TV.

Finally, a circle on the PC will not necessarily be a circle on the TV. It is likely to be an ellipse. To correct this the image needs to be stretched horizontally or subjects will look long and thin. dpexpert has found on two different TVs that about 10 per cent horizontal stretch results in a true circle. (In Photoshop go Edit/Transform/Scale and add 10 per cent in the horizontal insert box).

When the image is resized, gamma is reset and circles are corrected it is ready to drop into Nero or Memories on TV. These applications then step through menu creation, set slide transitions and durations and generate the MPEG2 file. Let the digital slide show begin.