Comparison between the GC counts measured in the MATLAS CFHT images and those measured from the HST images after background and completeness corrections have been applied. The light coral, light blue and light green circles are for GC detection in the CFHT images using three (u − g, g − r, g − i), two (g − r, g − i), and one (g − r) colours, respectively. The size of the symbol decreases with increasing distance. We do not find any trend between how many colours were used to identify the GCs in the CFHT images and the agreement with the HST GC numbers. As expected, the scatter is large but there is a clear agreement in the general trend; namely, the UDGs with the largest number of GC candidates in the ground-based images remain the same UDGs that have the largest GC candidates in the higher resolution HST images. The large scatter at the low CFHT N_GC values is most likely an effect of distance as the GC selection in the CFHT data was based on a fixed apparent magnitude cut.