Thermal transfer sheet, and combination of thermal transfer sheet and intermediate transfer medium

A thermal transfer sheet comprising:

• a substrate;
• and
• a transfer layer,
• wherein the transfer layer contains a luster pigment,
• wherein the luster pigment is a coated pigment including a core and a covering material that covers the core,
• wherein the core contains glass, and the covering material contains gold or silver,
• wherein, when an image of the thermal transfer sheet is taken from a side on which the transfer layer is present using an optical microscope at a 500-fold magnification in order to obtain an 8-bit grayscale image, the image is analyzed with image analysis software, dark and light portions of the analyzed image are inverted, automatic thresholding is then performed by an ISODATA method in order to determine a threshold value of a brightness distribution of the analyzed image, binary representation is subsequently performed such that portions in which brightness is less than the threshold value are colored in black and portions in which brightness is equal to or more than the threshold value are colored in white, and the number and the total area of the black portions and the total area of the white portions are calculated,
• wherein a ratio of the total area of the black portions to the total area of the white portions is 0.03 or more and 0.5 or less, and
• wherein the black portions have an average area of 100 μm2 or more and 300 μm2 or less.