<p>The present invention relates to methods of quality control of manufactured nucleic acid arrays. Fluorescence detection is used to evaluate the quality of a printed nucleic acid array prior to its use in hybridization without the need to add or otherwise link a fluorescent compound or dye to the nucleic acid. Nucleic acid arrays suitable for this method are those where the spots of the array are formed by printing a solution that contains the nucleic acid in an ion containing solution. Printing quality may be evaluated by measuring the intensity of fluorescence at the location of each printed sample, and/or by measuring the "morphology" (i.e. shape) of the printed sample. Printed spots can be "imaged" by measuring fluorescence across a spotted sample in two dimensions. The resulting image of a printed spot can be compared with a reference printed image expected for the printing equipment and solid phase used.</p>
