Image pixels are changed when plotting to PDF

[Anonymous]

Hello,

I have an low pixel image in AutoCAD (first picture) that changes pixel colours when plotted to PDF (Second picture). It appears the pixels are blended with the surroundings pixels.  I am viewing the image in AutoCAD with IMAGEQUALITY set to Draft Mode.  I have changed the raster DPI settings in Graphics section but this has had no effect. 

Any ideas what could be causing this?

Version: AutoCAD® Map 3D 2017 

Thanks.

[Libbya]

Why are you posting this on the Dynamic Blocks forum?

[ChicagoLooper]

What is your 'plotter setting?' Try changing your Autocad PDF pc.3 to a higher resolution. Note: this will not turn your original low resolution image into a high resolution image. It will merely improve the PDF 'output' during your plot process--you're still using your low res image.

Autocad PDF pc.3 settings.