Gray steps printed on the same sheet of Hahnemühle Photo Rag 308 using different printers and settings as indicated. Note the grays from P900 (rows 6 and 7) are pretty neutral, as are the final gray scales from R2880 (rows 1 and 2). All other rows printed with the R2880 have a color cast. Printing started from below, because otherwise the paper sensors of the P900 would not have correctly recognized the paper size. Since the image was taken with a smartphone the colors are not correct. Actually, the two lowest rows appear too neutral.

Prints Show a Magenta Color Cast

There are many reasons why prints may show a color cast. In my case, the prints from my Epson R2880 all the sudden came out with a slight magenta color cast. Since one or two nozzles were clogged, I performed an Auto Nozzle Check and Cleaning (C). Thereafter, the nozzle check showed all nozzles were fine. Curiously enough, the color cast seemed to have appeared just after the (apparently successful) Auto Nozzle Check and Cleaning (C).

The color cast from the R2880 became obvious when comparing the same image printed on the Epson P900. To pinpoint the problem I made a 10-step gray scale (16 bit ProPhotoRGB) and printed this step from Photoshop (under Win10) on Hahnemühle Photo Rag 308. The drivers were v6.63 (R2880) and v6.80 (P900). The PS settings were: PS Manages Colors, Normal Printing, Relative Colorimetric. In the printer driver I selected: Velvet Fine Art Paper, Color, No Color Management.

As seen from the photo on the left (taken with a smartphone) the grays from the P900 are almost neutral when using both the ICC profile of Hahnemühle (row 7 from above) and the printer's ABW mode (row 6). In case of the R2880 one can see a magenta color cast in the mid tones, in particular, when using the ICC profile provided by Hahnemühle (rows 3,4,5 and 8,9). Using a custom profile made with a ColorMunki Photo yielded a similar result (not shown). Using the R2880 in ABW mode only marginally reduces the color cast. In all cases the nozzle checks looked fine (not shown).

To quantify the color cast(s), I measured the printed colors using the ColorMunki Photo. The figure below shows the 'a' and 'b' values for the four cases (R2880, ICC, orange), (R2880, ABW, red), (P900, ICC, green) and (P900, ABW, blue) from the four lowest rows in above photo with the gray steps. The 'b' values are plotted versus the 'a' values. Along each line the brightness varies starting from black (L=0, indicated by the symbols x or +) to L=95. The dots indicate the (a,b) values of the color measured for the gray patch with the nominal Lab value (L,a,b)=(50,0,0) (see figure above). The largest color cast arises for the case (R2880, ICC) indicated by the orange dot, where the color of the patch with the nominal value (L,a,b)=(50,0,0) prints as (L,a,b)=(49,5.4,-1.4). It is obvious that deviations from neutrality (a=b=0) of the order of a=3 to a=5 are well visible.

/a-b-Plot
Variation of the printed color (in (a,b) values) measured along a row of gray patches (lines) for row 9 (orange) and other rows as indicated in the legend of the figure. The black dot shows the paper white of Photo Rag 308 and the gray disk indicates an error of dE=0.6.

The data for the P900 are relatively close to the measured paper white of Hahnemühle Photo Rag 308 (black dot, Lab=(96,0.2,1.8)). The solid gray disk should indicate the typical error of ColorMunki Photo (somewhere I found the value dE=0.6).

Then I did the following.

  1. Since the light cyan (LC) ink cartridge ran low, I replaced it. But this did not yield any significant change.
  2. Then I went back to the earlier driver version 6.62 for the R2880 and shook the light magenta (LM) cartridge (which was still quite full). But no improvement.
  3. Then I also replaced the cyan (C) cartridge which was consumed up to 20% or so. But no improvement either.
  4. Then I did a Head Cleaning (H) (not the Auto Nozzle Check and Cleaning (C)) and printed the gray scale using my own ICC-hk profile: Success.
  5. Thereafter, I also printed the gray step using the generic Hahnemühle ICC profile. The result was also good visibly.

After the Head Cleaning (H) I measured the gray patches using the generic ICC profile for the R2880 (row 1) and using my own custom ICC profile (row 2). The results are shown as dashed lines in the plot. The custom profile makes slight excursions into the yellow range (violet dashed), while the generic Hahnemühle profile yields a more blue-magenta cast (orange dashed). The accuracy of the reproduction of the grays by the P900 with the generic ICC profile is about the same as by the R2880 using my custom profile. As perhaps expected, the neutrality is improved when using the Advanced Black and White mode (ABW) of the P900 (blue line). Some deviations from neutrality remain when using the ICC profiles. But these seem to be acceptable when noticing the color deviation of the paper base from pure white is about dE=2.

My conclusion is that the Head Cleaning (H) has more or less solved the magenta color cast problem, even though the first Auto Nozzle Check and Cleaning (C) seemed to have initiated the whole problem. Most likely I need to print more ...

November 2022