diff --git a/skimage/_shared/testing.py b/skimage/_shared/testing.py
index db3bcfe8..f8c7a88e 100644
--- a/skimage/_shared/testing.py
+++ b/skimage/_shared/testing.py
@@ -100,8 +100,8 @@ def roundtrip(img, plugin, suffix):
     return new
 
 
-def ubyte_check(plugin, fmt='png'):
-    """Check roundtrip behavior for images that can only be saved as uint8
+def color_check(plugin, fmt='png'):
+    """Check roundtrip behavior for color images.
 
     All major input types should be handled as ubytes and read
     back correctly.
@@ -132,11 +132,10 @@ def ubyte_check(plugin, fmt='png'):
     testing.assert_allclose(r5, img)
 
 
-def full_range_check(plugin, fmt='png'):
+def mono_check(plugin, fmt='png'):
     """Check the roundtrip behavior for images that support most types.
 
-    All major input types should be handled, except bool is treated
-    as ubyte and float can treated as uint16 or float.
+    All major input types should be handled.
     """
 
     img = img_as_ubyte(data.moon())
@@ -169,7 +168,7 @@ def full_range_check(plugin, fmt='png'):
 
 
 if __name__ == '__main__':
-    ubyte_check('pil')
-    full_range_check('pil')
-    ubyte_check('pil', 'bmp')
-    full_range_check('pil', 'tiff')
+    color_check('pil')
+    mono_check('pil')
+    mono_check('pil', 'bmp')
+    mono_check('pil', 'tiff')
diff --git a/skimage/io/tests/test_pil.py b/skimage/io/tests/test_pil.py
index 7b5cdd49..ee9add79 100644
--- a/skimage/io/tests/test_pil.py
+++ b/skimage/io/tests/test_pil.py
@@ -8,7 +8,7 @@ from tempfile import NamedTemporaryFile
 from skimage import data_dir
 from skimage.io import (imread, imsave, use_plugin, reset_plugins,
                         Image as ioImage)
-from skimage._shared.testing import ubyte_check, full_range_check
+from skimage._shared.testing import mono_check, color_check
 
 from six import BytesIO
 
@@ -157,13 +157,13 @@ def test_imexport_imimport():
 
 
 def test_all_color():
-    ubyte_check('pil')
-    ubyte_check('pil', 'bmp')
+    color_check('pil')
+    color_check('pil', 'bmp')
 
 
 def test_all_mono():
-    full_range_check('pil')
-    full_range_check('pil', 'tiff')
+    mono_check('pil')
+    mono_check('pil', 'tiff')
 
 
 class TestSaveTIF: