Greyscale photos can be flat and lack sparkle.
Post processing is the secret to improving dull images and Irfanview is quick and easy to
Rather than hit the greyscale button, better effects can be achieved by first using the "Color Corrections" function.
Choose settings that make the photo more vivid and using the contrast and gamma functions help to find a more balanced
Then hit the "Auto adjust colours" button followed by "convert to greyscale"
Here is and example of Before and After...