Halftone proofers are hybrid contone-raster proofers: their working principle is similar to contone proofers, but their result is similar to raster proofs. Half-tone proofers use the original PS/PDF file, process it with their internal PS/PDF interpreter, apply the right colour management, and print it on the colour printer as a halftoned image, using a halftone structure that is as similar as possible to the target (simulated) halftone.
Because the job will be interpreted twice, there is a slight chance of content differences (though in StudioRIP they will be interpreted by the same PS engine under the same conditions, so this chance is little more than theoretical).
Advantages
- Color accuracy: the typical colour accuracy is about ΔE = 1
- Fairly good halftone simulation: although not keeping the original dot structure, the halftones are very similar and most differences are invisible to the naked eye.
Disadvantages
- Data integrity: there is a slight theoretical chance for content differences between the proof and the print.
- Lower speed: the file needs to be processed twice.
- Imposition: only automatic impositions, that can be replicated in the proofing process, can be simulated.
