| diff --git a/third_party/libtiff/tif_dir.c b/third_party/libtiff/tif_dir.c |
| index 73212c02d..16ce3d3ce 100644 |
| --- a/third_party/libtiff/tif_dir.c |
| +++ b/third_party/libtiff/tif_dir.c |
| @@ -426,6 +426,14 @@ _TIFFVSetField(TIFF* tif, uint32 tag, va_list ap) |
| case TIFFTAG_REFERENCEBLACKWHITE: |
| /* XXX should check for null range */ |
| _TIFFsetFloatArray(&td->td_refblackwhite, va_arg(ap, float*), 6); |
| + for (int i = 0; i < 6; i++) { |
| + if (isnan(td->td_refblackwhite[i])) { |
| + if (i % 2 == 0) |
| + td->td_refblackwhite[i] = 0; |
| + else |
| + td->td_refblackwhite[i] = pow(2, td->td_bitspersample) - 1; |
| + } |
| + } |
| break; |
| case TIFFTAG_INKNAMES: |
| v = (uint16) va_arg(ap, uint16_vap); |