diff --git a/src/libImaging/JpegEncode.c b/src/libImaging/JpegEncode.c
index 3c11eac22..a2e2945bc 100644
--- a/src/libImaging/JpegEncode.c
+++ b/src/libImaging/JpegEncode.c
@@ -178,12 +178,13 @@ ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) {
                 if (context->quality != -1) {
                     quality = context->quality;
                 }
+                int scale_factor = jpeg_quality_scaling(quality);
                 for (i = 0; i < context->qtablesLen; i++) {
                     jpeg_add_quant_table(
                         &context->cinfo,
                         i,
                         &context->qtables[i * DCTSIZE2],
-                        quality,
+                        scale_factor,
                         FALSE
                     );
                     context->cinfo.comp_info[i].quant_tbl_no = i;
@@ -193,7 +194,7 @@ ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) {
                     // jpeg_set_defaults created two qtables internally, but we only
                     // wanted one.
                     jpeg_add_quant_table(
-                        &context->cinfo, 1, &context->qtables[0], quality, FALSE
+                        &context->cinfo, 1, &context->qtables[0], scale_factor, FALSE
                     );
                 }
                 for (i = last_q; i < context->cinfo.num_components; i++) {