QuickSilver uses a combination of specialised Computer Assisted Translation (CAT) and Translation Memory (TM) software which searches a powerpoint presentation (PPT) and extracts the text into an editable format.
Having extracted the text, we then translate it using a TM before putting it back into the PPT. Here the story would end, or at least it would if every text string in the translation had precisely the same number of characters as the source. This is almost never the case, however, and adjustments to the formatting therefore need to be made at each point. This process is sometimes referred to as tweaking.
Linguistic desktop publishing experts know how to put together PPTs in such a way that they will accommodate any translations of the text – (very) basically, by leaving enough space. Unfortunately, people with no experience of working with multilingual documentation put together PPTs in a rather ad hoc way, which means that a significant amount of tweaking is needed to fit a translation. Remember that a Spanish translation, for example, generally occupies around 20% more space than the equivalent text in English: if the slide is already full of text or images, then it requires considerable thought, work and re-design to make space for that extra 20%.
Another thing to be aware of is that, if diagrams or other illustrations are integrated into the PPT as an image (a jpeg, for example), and they contain text, that text will be uneditable. The whole image would then have to be reworked from scratch. For this reason, it is better to integrate images on their own, and then put in the text as a normal (editable) text box.
Unnecessary effort and expense can be avoided by giving QuickSilver control over the design of the layout. Even with more general programs like PowerPoint, it is a failsafe way to reduce costs and time-to-market.