**Table 1:** Residuals between datasets from different sources. These are given as X₂-X₁ where X is the studied variable from the data sources 1 and 2.
X	S1	S2	N	m_X	$\sigma$
$\Delta_{VV}$	$\mu_V(1)$	$\mu_V(2)$	13	-0.014	0.044
$\Delta _{VJ}$	dVJ(1)	dVJ(2)	14	0.015	0.045
$\Delta _{VK}$	dVK(1)	dVK(2)	14	0.015	0.047
$\Delta _{BV}$	IMP02+	Gal94	21	-0.003	0.028
$\Delta_{VI}$	IMP02+	Gal94	15	-0.019	0.034
$\Delta_{BR}$	IMP02+	Pal90	18	-0.010	0.030
$\Delta_{UR}$	IMP02+	Pal90	18	-0.010	0.065

(1) Variable X; (2), (3) sources S1, S2 with abbreviated keys: $\mu_V(1)$ , V-profile from OHP frames; $\mu_V(2)$ , V-profile from Gal94; dVJ(1), $\Delta _{VJ}$ from 2MASS and OHP frames; dVJ(2), $\Delta _{VJ}$ from 2MASS and Gal94 V-profiles; dVK(1) and dVK(2), same sources for $\Delta _{VK}$ . Source IMP02 contains data from this reference and from miscellaneous OHPframes; (4) N number of data; (5) m_X mean residual; (6) standarddeviation $\sigma$ .

Source LaTeX | All tables | In the text

	1 Introduction
	2 Collecting the gradients
	3 Properties of colour gradients
	4 Simulated datasets of colour gradients
	5 Concluding summary
	References