How does it look if you go to the View men > Display Performance > and select High Quality?
made the background transparent using "colour range" in Photoshop
The problem could be with your color range technique. The feathering from the background into the lettering might not be as good as you think. Have you checked your Photoshop mask by adding a colored layer underneath?
Here I've masked the text using color range and it looks OK on a white background, but on gray there is a fringe
An alternate method would be to place the scan with no transparency mask and set it to multiply. The bottom version is flat and set to multiply in InDesign:
I used Image Trace in Illustrator for my signature. Did you play with the settings or use Default? The Preset called "Default" is Black and White, which is fine. It also creates Fills. I don't remember all the tweaks I made, as it was a number of years ago, but I know I selected Strokes, not Fills. Then I edited the Path afterwards to smooth it out—deleting and redrawing Anchor points until it looked like my signature. I saved it in .ai, .pdf, and as a custom stamp in Acrobat.
Spin open "Advanced" to see the options.
Also, I signed it very large and scanned it at 600 ppi before bringing it into Illustrator to trace.
Do you have an iPad?
Use Adobe Draw with any stylus or even your finger to create a vector version of your signature.
From there you can create a custom PDF stamp or just save it in a CC library.
This isn't an InDesign issue... if you want pure black text on transparency, you'll need to use the proper technique in Ps.
There are several ways to accomplish this... here's one:
- Start by making sure the white parts of your image are pure white (use levels or a curve).
- From there, go to your channels tab and cmd/ctrl click one of the channels... this will turn the black part of your image into a selection.
- Go back to your layers panel, create a new layer, invert your selection and then fill with black.
- Save as PSD and you'll have a perfectly transparent signature
For this purpose do following:
- Save the file in Photoshop as TIFF or PSD without layers.
- Change to Bitmap-Mode (1bit), take a resolution 4 x so high as you would do it normally. As it has only 1 bit it has not a huge file size
- Place it in InDesign.
- With the direct selectiobn tool you can color it.