The choice of the best binarization algorithm is very critical for any document image processing system, since it is one of the first tasks and any mistake it performs will be carried through the whole system. Here, a new technique for the validation of document binarization algorithms is proposed. Our method is simple in its implementation and it can be applied to any binarization algorithm since it doesn't require anything more than the binarization stage. It is based on the use of synthetic images from pdf document. Then the binarization algorithm is applied and the result is compared with the original pdf. Categories and Subject Descriptors I.7.5 [Document and text processing]: Document Capture