It's very difficult to do accurate image editing on a laptop.... and I imagine on a pad. Both are subject to whatever ambient light is where they are being used. And, viewing angles change so easily, even a little can make for huge differences.
It's probably a combination of overly bright display and color balance. Most lcd screens are way too bright. For editing, I'm also using a 24" IPS monitor with a matte display (HP LP2475w in my case). I have brightness turned way down to 21 (out of 100). I check that and run calibration on it monthly.
I also use a hood to minimize stray light on the monitor and my workspace has fairly well controlled and somewhat dimmed lighting.
I also use a couple laptops, just not for critical image editing work. But, I do keep them calibrated as well, as best possible.
It also can make a difference the program in which you are viewing images. For example, Windows Explorer isn't color calibrated, so images do not appear true color on the web or if viewing them on my computer with that program... colors tend to look flat and washed out. Lightroom and Photoshop and other softwares I use are calibrated. (I have a codec installed, though, that allows directly viewing RAW files in Explorer and displays them with a high degree of color accuracy. Canon offers a codec for 32 bit operating systems, but last time I checked not for 64 bit. So I bought an inexpensive codec called FastPictureViewer and installed it. That allows directly viewing RAWs, calibrated, in Explorer... Not just Canon's either.... all camera manufacturers' files are supported.)
Further, it depends upon the image files themselves. For example, I shoot in Adobe RGB and RAW, work with them in 16 bit mode, but then save images that will be used to make prints or posted online as 8 bit sRGB JPEGs. If saved as another type of file, such as a TIFF or PSD, color is truer, 16 bit can be maintained and they can be left in Adobe RGB color space.
I do recommend calibrating your displays. Every photographer should, to avoid frustration editing their images and making prints. I'm using Datacolor Spyder3 Elite, but only because it allows me to calibrate the three computers I use, plus calibrate a projector and make print profiles, if needed. You could probably get by with a lighter calibration suite that only calibrates your monitor. I haven't got a pad, so have never tried to calibrate one... but Apple products are fairly well respected for color fidelity, so it might not be needed. Mainly I recommend one that checks monitor brightness levels. Not all of them do, yet it's one of the most critical factors. I shoot for a 90 to 100 cd/m^2 for my main editing monitor. That pretty well matches prints I make from it (if you have overly dark prints, that's a sign your computer monitor is overly bright... If needed, you can use a good print from a sample image to adjust brightness reasonably accurately, via the monitor menu).
Some of the calibration devices also can measure ambient light and adjust for it on the fly. That might be helpful using a laptop. But nothing can solve the problem of easily varied viewing angles. You can see for yourself how it can be an issue.... just set up your laptop, get an image on the screen, then change the tilt it slightly and see how much it changes. Most laptop monitors also vary a lot if viewed from any angle. It's hard to be consistent enough maintaining identical viewing angles with a laptop.