Any document that you intend to transmit by fax warrants certain design considerations. The document doesn’t necessarily have to be a dedicated fax form or fax cover sheet. It could by any document that is frequently faxed, for instance, an invoice, purchase order, sales order, or credit application.
To achieve maximum readability out of facsimile transmissions of documents, avoid the use of screened (shaded) areas, because these can obscure information contained within them when the document is faxed.
Avoid the use of large reverse-printed (white text on a solid background) blocks of copy, because this heavy ink coverage slows down transmission time. Reverse printed text is often distorted by fax transmission, making it difficult to read.
Avoid the use of heavy rules (writing lines), because data typed or written over a heavy rule will be obscured by the rule on the transmitted copy. For example, the tail of a numeral 2 can blend in with a heavy rule and make it appear on the transmitted copy as a 7. Decimal points can be lost all together within a heavy rule so that 2.0 might appear as a 20 or 70 on the transmitted copy. Solve the problem of heavy rules by having rules screened to a 10% density which makes them very faint. Written or typed information is easily discernible against a faint rule. Other options are to use a very fine rule, ½ point in thickness or less, or eliminate rules completely.
Information that you wish the recipient of the fax transmission to read should be printed in a dark color of ink. Especially avoid the use of light blue ink as the fax scanner tends to ignore that color and the information will not be transmitted. Avoid the use of very small, fine type as this often distorts in transmission.
Follow these suggestions and you will improve the readability of documents that are transmitted by fax.