DENSS now has a new mode for membrane proteins. Membrane proteins are often solubilized in detergents or lipid nanodiscs. The hydrophobic regions of these molecules often have lesser scattering density than the bulk solvent, resulting in a negative contrast relative to the solvent. The default setting for DENSS enforces a positivity restraint that will not allow any density to be negative. While this is appropriate for most standard biomolecules such as proteins and nucleic acids, is it not appropriate for molecules containing regions of negative contrast. To accommodate this scenario, there is a new MEMBRANE mode in addition to the previously available FAST and SLOW modes. This mode disables the positivity restraint and starts shrink-wrap immediately. As the negative of an image has the same Fourier transform as the images, the sign is ambiguous. To help ensure the positive and negative regions are most consistent when averaging, denss() now checks if there is greater negative density than positive density before saving the final map. If so, the map is multiplied by -1. This does not ensure the sign of the density is correct, just that the sign of the density is most likely to be the same for multiple reconstructions for averaging. See the Basic Usage tutorial page for more details on how to use this new mode.