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We present the first scattered-light images of two debris disks around the F8star HD 104860 and the F0V star HD 192758, respectively $\sim45$ and $\sim67$pc away. We detected these systems in the F110W and F160W filters through ourre-analysis of archival Hubble Space Telescope NICMOS data with modernstarlight subtraction techniques. Our image of HD 104860 confirms themorphology previously observed by Herschel in thermal emission with awell-defined ring at radius $\sim114$ au inclined $\sim58$ degrees. Althoughthe outer edge profile is consistent with dynamical evolution models, the sharpinner edge suggests sculpting by unseen perturbers. Our images of HD 192758reveal a disk at radius $\sim95$ au inclined by $\sim59$ degrees, neverresolved so far. These disks have low scattering albedos of 10% and 13%respectively, inconsistent with water ice grain compositions. They arereminiscent of several other disks with similar inclination and scatteringalbedos: Fomalhaut, HD 92945, HD 202628, and HD 207129. They are also verydistinct from brighter disks in the same inclination bin, which point todifferent compositions between these two populations. Varying scattering albedovalues can be explained by different grain porosities, chemical compositions,or grain size distributions, which may indicate distinct formation mechanismsor dynamical processes at work in these systems. Finally, these faint diskswith large infrared excesses may be representative of an underlying populationof systems with low albedo values. Searches with more sensitive instruments onHST or on the James Webb Space Telescope and using state-of-the artstarlight-subtraction methods may help discover more of such faint systems.

HD 104860 and HD 192758: two debris disks newly imaged in scattered-light with HST