diff --git a/colour/colorimetry/spectrum.py b/colour/colorimetry/spectrum.py
index 04e4b7bcc..4a3864130 100644
--- a/colour/colorimetry/spectrum.py
+++ b/colour/colorimetry/spectrum.py
@@ -903,6 +903,9 @@ def interpolate(
             Interpolator class type to use as interpolating function.
         interpolator_kwargs
             Arguments to use when instantiating the interpolating function.
+        interpolation_method
+            Interpolation method, ``Continuous`` uses the underlying continuous
+            signal and supports fractional steps.
 
         Returns
         -------
@@ -1177,17 +1180,10 @@ def interpolate(
             ]
         )
 
-        # Defining proper interpolation bounds.
-        # TODO: Provide support for fractional interval like 0.1, etc...
-        if np.around(shape_start) != shape_start or np.around(shape_end) != shape_end:
-            runtime_warning("Fractional bound encountered, rounding will occur!")
-
-        shape.start = max([shape.start, np.ceil(shape_start)])
-        shape.end = min([shape.end, np.floor(shape_end)])
+        shape.start = max([shape.start, shape_start])
+        shape.end = min([shape.end, shape_end])
 
         if interpolator is None:
-            # User has specifically chosen the interpolator thus it is used
-            # instead of those from *CIE 167:2005* recommendation.
             if self.interpolator not in (
                 SpragueInterpolator,
                 CubicSplineInterpolator,
@@ -1199,8 +1195,6 @@ def interpolate(
                 interpolator = CubicSplineInterpolator
 
         if interpolator_kwargs is None:
-            # User has specifically chosen the interpolator thus its keyword
-            # arguments are used.
             if self.interpolator not in (
                 SpragueInterpolator,
                 CubicSplineInterpolator,
@@ -1209,12 +1203,19 @@ def interpolate(
             else:
                 interpolator_kwargs = {}
 
-        wavelengths, values = self.wavelengths, self.values
+        self_interpolator, self.interpolator = self.interpolator, interpolator
+        self_interpolator_kwargs, self.interpolator_kwargs = (
+            self.interpolator_kwargs,
+            interpolator_kwargs,
+        )
+
+        values = self[shape.wavelengths]
 
         self.domain = shape.wavelengths
-        self.range = interpolator(wavelengths, values, **interpolator_kwargs)(
-            self.domain
-        )
+        self.values = values
+
+        self.interpolator = self_interpolator
+        self.interpolator_kwargs = self_interpolator_kwargs
 
         return self
 
diff --git a/colour/colorimetry/tests/test_spectrum.py b/colour/colorimetry/tests/test_spectrum.py
index c72a1ad1f..bdf2a7316 100644
--- a/colour/colorimetry/tests/test_spectrum.py
+++ b/colour/colorimetry/tests/test_spectrum.py
@@ -615,422 +615,422 @@
     0.000000000000000,
     0.000000000000000,
 )
-
 DATA_SAMPLE_INTERPOLATED_NON_UNIFORM: tuple = (
-    16.329808636577400,
-    16.722487609243078,
-    17.780769796558388,
-    19.388440919210822,
-    21.429286697887836,
-    23.787092853276910,
-    26.345645106065515,
-    28.988729176941121,
-    31.600130786591194,
-    34.063635655703216,
-    36.263029504964656,
-    38.082098055062993,
-    39.404627026685688,
-    40.114402140520198,
-    40.111247588026082,
-    39.925103635141149,
-    39.890167058876870,
-    39.799323872976096,
-    39.680556569501256,
-    39.561845869769570,
-    39.471172495098209,
-    39.436517166804364,
-    39.485860606205222,
-    39.647183534617994,
-    39.948466673359860,
-    40.374181475729280,
-    40.480943048717741,
-    39.587763146544347,
-    37.399010971904012,
-    34.259517350145224,
-    30.574008069142096,
-    26.747208916768866,
-    23.183845680899680,
-    20.288644149408725,
-    18.466330110170176,
-    18.131455040802454,
-    19.618408431271092,
-    22.601624593221480,
-    26.621530082560952,
-    31.218551455196845,
-    35.933115267036499,
-    40.312773209586069,
-    44.121677838324345,
-    47.374686358105983,
-    50.100647613008405,
-    52.328410447109043,
-    54.086823704485290,
-    55.404736229214613,
-    56.310996865374428,
-    56.834454457042114,
-    57.003957848295137,
-    56.848355883210893,
-    56.396497405866839,
-    55.677231260340363,
-    54.719406290708918,
-    53.551871341049903,
-    52.203475255440743,
-    50.703066877958868,
-    49.079495052681693,
-    47.361608623686649,
-    45.578256435051173,
-    43.758287330852653,
-    41.930550155168532,
-    40.123893752076235,
-    38.367166965653183,
-    36.689218639976801,
-    35.118897619124496,
-    33.685052747173714,
-    32.416532868201863,
-    31.342186826286373,
-    30.490863465504646,
-    29.891411629934137,
-    29.572680163652254,
-    29.538621481156376,
-    33.594913456316092,
-    41.048330705400552,
-    45.551744552213606,
-    47.142069193311166,
-    46.264235269850914,
-    43.363173422990592,
-    38.883814293887831,
-    33.271088523700378,
-    26.969926753585888,
-    20.425259624702068,
-    14.082017778206605,
-    8.385131855257200,
-    3.728429425651282,
-    0.156961054721180,
-    -2.429909888236355,
-    -4.133307786198728,
-    -5.054357022143353,
-    -5.294181979047651,
-    -4.953907039889023,
-    -4.134656587644884,
-    -2.937555005292646,
-    -1.463726675809728,
-    0.185704017826468,
-    1.909612692638526,
-    3.606874965649032,
-    5.176366453880572,
-    6.516962774355742,
-    7.527539544097118,
-    8.122379803803623,
-    8.331483144611147,
-    8.237444938631239,
-    7.923124732066758,
-    7.471382071120567,
-    6.965076501995521,
-    6.487067570894484,
-    6.120214824020312,
-    5.947377807575871,
-    6.051416067764015,
-    6.515189150787608,
-    7.421556602849507,
-    8.833103319101975,
-    10.654113909347958,
-    12.714472051171430,
-    14.843629856075644,
-    16.871039435563851,
-    18.626152901139314,
-    19.938422364305275,
-    20.637299936564997,
-    20.706835013628812,
-    20.713132276905259,
-    20.620587314150111,
-    20.396819412610807,
-    20.054405097058748,
-    19.605938071902443,
-    19.064012041550384,
-    18.441220710411045,
-    17.750157782892924,
-    17.003416963404511,
-    16.213591956354293,
-    15.393276466150766,
-    14.555064197202412,
-    13.711548853917725,
-    12.875324140705192,
-    12.058983761973309,
-    11.275121422130562,
-    10.536330825585436,
-    9.855205676746426,
-    9.244339680022023,
-    8.716326539820709,
-    8.283759960550988,
-    7.959233646621334,
-    7.755341302440248,
-    7.684676632416213,
-    7.756084346822568,
-    7.961801724157814,
-    8.289468950531905,
-    8.726726048591537,
-    9.261213040983417,
-    9.880569950354237,
-    10.572436799350699,
-    11.324453610619505,
-    12.124260406807357,
-    12.959497210560945,
-    13.817804044526978,
-    14.686820931352152,
-    15.554187893683173,
-    16.407544954166731,
-    17.234532135449530,
-    18.022789460178267,
-    18.759956950999651,
-    19.433674630560375,
-    20.031582521507140,
-    20.541320646486646,
-    20.950529028145592,
-    21.246847689130675,
-    21.417916652088600,
-    21.451375939666065,
-    21.334865574509770,
-    21.056025579266414,
-    20.604750276779001,
-    20.494345115463702,
-    22.221705466331883,
-    25.661450384670388,
-    29.775598875658655,
-    33.531925166546948,
-    36.383260993760757,
-    38.399428506854193,
-    39.690190939354423,
-    40.365311524788659,
-    40.534553496684069,
-    40.307680088567857,
-    39.794454533967205,
-    39.104640066409281,
-    38.347999919421312,
-    37.634297326530451,
-    37.374685121273394,
-    39.119690201154867,
-    40.253206513156250,
-    38.299118522290833,
-    34.130306343480264,
-    28.883500017392159,
-    23.695429584694160,
-    19.702825086053920,
-    18.042370406596557,
-    17.942146149526579,
-    17.437952042997388,
-    16.603615436175311,
-    15.527509997088327,
-    14.298009393764401,
-    13.003487294231499,
-    11.732317366517600,
-    10.572873278650665,
-    9.613528698658669,
-    8.942657294569587,
-    8.648632734411382,
-    8.638275005914387,
-    8.608461770725761,
-    8.468358277399256,
-    8.236485894689265,
-    7.918459394063972,
-    7.519893546991550,
-    7.046403124940173,
-    6.503602899378026,
-    5.897107641773280,
-    5.232532123594114,
-    4.515491116308703,
-    3.751599391385226,
-    2.946471720291860,
-    2.105722874496783,
-    1.234967625468170,
-    0.339820744674198,
-    -0.574102996416954,
-    -1.501188826337108,
-    -2.435821973618090,
-    -3.372387666791723,
-    -4.305271134389827,
-    -5.228857604944231,
-    -6.137532306986749,
-    -7.025680469049206,
-    -7.887687319663434,
-    -8.717938087361247,
-    -9.510818000674471,
-    -10.260712288134929,
-    -10.962006178274445,
-    -11.609084899624833,
-    -12.196333680717927,
-    -12.718137750085543,
-    -13.168882336259514,
-    -13.542952667771653,
-    -13.834733973153785,
-    -14.038611480937735,
-    -14.148970419655322,
-    -14.160196017838375,
-    -14.066673504018716,
-    -13.862788106728164,
-    -13.542925054498539,
-    -13.101469575861673,
-    -12.532806899349385,
-    -11.831322253493493,
-    -10.991400866825831,
-    -10.007427967878208,
-    -8.873788785182459,
-    -7.584868547270405,
-    -6.135052482673858,
-    -4.518725819924658,
-    -2.730273787554616,
-    -0.764081614095559,
-    1.385465471920696,
-    3.723982241962316,
-    6.257083467497486,
-    8.990383919994379,
-    11.929498370921175,
-    14.976162260830137,
-    5.084237255461949,
-    -6.729230790271000,
-    -14.622433089729542,
-    -19.038838171389944,
-    -20.421914563728482,
-    -19.215130795221405,
-    -15.861955394344996,
-    -10.805856889575507,
-    -4.490303809389212,
-    2.641235317737622,
-    10.145291963328749,
-    17.578397598907866,
-    24.497083695998736,
-    30.457881726125084,
-    35.017323160810655,
-    37.731939471579153,
-    38.169944675202451,
-    36.103648065327157,
-    31.478944095141092,
-    24.247257545409393,
-    14.377470469911161,
-    2.089605892978410,
-    -12.208009328653077,
-    -28.102486071018522,
-    -45.180935210153116,
-    -63.030467622092019,
-    -81.238194182870473,
-    -99.391225768523640,
-    -117.076673255086732,
-    -133.881647518594917,
-    -149.393259435083451,
-    -163.198619880587444,
-    -174.884839731142108,
-    -184.039029862782684,
-    -190.248301151544382,
-    -193.099764473462415,
-    -192.180530704571822,
-    -187.077710720907902,
-    -177.378415398505837,
-    -162.669755613400923,
-    -142.538842241628146,
-    -116.572786159222886,
-    -84.358698242220214,
-    -45.483689366655454,
-    0.465129591436323,
-    53.867241377821607,
-    111.906385750398641,
-    165.969680931356891,
-    206.832112792864763,
-    225.268667207090687,
-    212.054330046203120,
-    157.964087182370434,
-    53.772924487761195,
-    24.128558965593012,
-    155.948189345952358,
-    238.667542187567193,
-    279.823268952005947,
-    286.952021100836475,
-    267.590450095627091,
-    229.275207397946076,
-    179.542944469361430,
-    125.930312771441450,
-    75.973963765754249,
-    37.210548913868003,
-    17.176719677350921,
-    17.152394375030820,
-    19.379794324130732,
-    21.517434431022508,
-    23.565545988087592,
-    25.524360287707406,
-    27.394108622263396,
-    29.175022284136993,
-    30.867332565709628,
-    32.471270759362753,
-    33.987068157477793,
-    35.414956052436175,
-    36.755165736619354,
-    38.007928502408760,
-    39.173475642185821,
-    40.252038448331973,
-    41.243848213228674,
-    42.149136229257330,
-    42.968133788799399,
-    43.701072184236310,
-    44.348182707949491,
-    44.909696652320392,
-    45.385845309730442,
-    45.776859972561077,
-    46.082971933193733,
-    46.304412484009845,
-    46.441412917390849,
-    46.494204525718175,
-    46.463018601373285,
-    46.348086436737596,
-    46.149639324192542,
-    45.867908556119552,
-    45.503125424900077,
-    45.055521222915552,
-    44.525327242547419,
-    43.912774776177095,
-    43.218095116186007,
-    42.441519554955640,
-    41.583279384867382,
-    40.643991169034841,
-    39.627797988936805,
-    38.540734852902020,
-    37.388854826093969,
-    36.178210973676094,
-    34.914856360811882,
-    33.604844052664760,
-    32.254227114398248,
-    30.869058611175774,
-    29.455391608160820,
-    28.019279170516839,
-    26.566774363407301,
-    25.103930251995678,
-    23.636799901445418,
-    22.171436376920010,
-    20.713892743582907,
-    19.270222066597562,
-    17.846477411127466,
-    16.448711842336071,
-    15.082978425386836,
-    13.755330225443233,
-    12.471820307668732,
-    11.238501737226787,
-    10.061427579280879,
-    8.946650898994456,
-    7.900224761530997,
-    6.928202232053956,
-    6.036636375726809,
-    5.231580257713018,
-    4.519086943176044,
-    3.905209497279358,
-    3.396000985186418,
-    2.997514472060695,
-    2.715803023065654,
-    2.556919703364760,
-    2.526917578121476,
-    2.631849712499274,
-    2.877769171661610,
-    3.270729020771954,
-    3.816782324993773,
-    4.521982149490528,
-    5.392381559425689,
-    6.434033619962720,
-    7.652991396265083,
+    16.33174000,
+    16.64993716,
+    17.64548368,
+    19.20219560,
+    21.20388894,
+    23.53437976,
+    26.07748407,
+    28.71701792,
+    31.33679734,
+    33.82063837,
+    36.05235704,
+    37.91576938,
+    39.29469143,
+    40.07293922,
+    40.14077612,
+    39.92419302,
+    39.89684762,
+    39.81049683,
+    39.69333189,
+    39.57332622,
+    39.47845324,
+    39.43668638,
+    39.47599905,
+    39.62436468,
+    39.90975669,
+    40.33304002,
+    40.50491197,
+    39.74501724,
+    37.67902112,
+    34.62018880,
+    30.97314049,
+    27.14249640,
+    23.53287675,
+    20.54890177,
+    18.59519166,
+    18.08081760,
+    19.38373812,
+    22.23096797,
+    26.16305357,
+    30.72054135,
+    35.44397775,
+    39.87706471,
+    43.74602436,
+    47.05613715,
+    49.83624442,
+    52.11518748,
+    53.92180764,
+    55.28494623,
+    56.23344457,
+    56.79614397,
+    57.00188576,
+    56.87951125,
+    56.45786176,
+    55.76577861,
+    54.83210312,
+    53.68567662,
+    52.35534040,
+    50.86993581,
+    49.25830415,
+    47.54928674,
+    45.77172491,
+    43.95445997,
+    42.12633325,
+    40.31618605,
+    38.55285970,
+    36.86519552,
+    35.28203483,
+    33.83221894,
+    32.54458918,
+    31.44798686,
+    30.57125331,
+    29.94322984,
+    29.59275777,
+    29.54381964,
+    32.79286157,
+    40.36558235,
+    45.21160576,
+    47.09673165,
+    46.46577457,
+    43.76354913,
+    39.43486990,
+    33.92455146,
+    27.67740839,
+    21.13825529,
+    14.75190672,
+    8.96317728,
+    4.18354245,
+    0.49841631,
+    -2.19120584,
+    -3.98642200,
+    -4.98833019,
+    -5.29802840,
+    -5.01661465,
+    -4.24518693,
+    -3.08484325,
+    -1.63668162,
+    -0.00180003,
+    1.71870349,
+    3.42373096,
+    5.01218436,
+    6.38296569,
+    7.43497695,
+    8.07693863,
+    8.32474693,
+    8.26027419,
+    7.96635835,
+    7.52583734,
+    7.02154908,
+    6.53633153,
+    6.15302259,
+    5.95446022,
+    6.02348233,
+    6.44292687,
+    7.29563177,
+    8.65167043,
+    10.43511482,
+    12.47696318,
+    14.60671211,
+    16.65385820,
+    18.44789806,
+    19.81832829,
+    20.59464547,
+    20.70989576,
+    20.71490257,
+    20.63782267,
+    20.42824992,
+    20.09863019,
+    19.66155390,
+    19.12961147,
+    18.51539332,
+    17.83148987,
+    17.09049153,
+    16.30498873,
+    15.48757188,
+    14.65083142,
+    13.80735774,
+    12.96974128,
+    12.15057246,
+    11.36244169,
+    10.61793939,
+    9.92965598,
+    9.31018188,
+    8.77210752,
+    8.32802330,
+    7.99051965,
+    7.77218699,
+    7.68561574,
+    7.74083122,
+    7.93173795,
+    8.24599287,
+    8.67123920,
+    9.19512022,
+    9.80527915,
+    10.48935925,
+    11.23500376,
+    12.02985593,
+    12.86155901,
+    13.71775624,
+    14.58609087,
+    15.45420615,
+    16.30974532,
+    17.14035164,
+    17.93366833,
+    18.67733867,
+    19.35900588,
+    19.96631322,
+    20.48690393,
+    20.90842126,
+    21.21850846,
+    21.40480878,
+    21.45496545,
+    21.35662174,
+    21.09742087,
+    20.66514352,
+    20.43751858,
+    21.91097080,
+    25.20288294,
+    29.29167835,
+    33.13704964,
+    36.09348577,
+    38.20199674,
+    39.57231714,
+    40.31418157,
+    40.53732465,
+    40.35148096,
+    39.86638512,
+    39.19177172,
+    38.43737537,
+    37.71293067,
+    37.32215353,
+    38.85348208,
+    40.28480326,
+    38.66906876,
+    34.70409378,
+    29.52631184,
+    24.27215647,
+    20.07806121,
+    18.08045957,
+    17.97606450,
+    17.51718098,
+    16.71767084,
+    15.66588470,
+    14.45017318,
+    13.15888689,
+    11.88037645,
+    10.70299247,
+    9.71508557,
+    9.00500637,
+    8.66110548,
+    8.63646961,
+    8.61886171,
+    8.49018794,
+    8.26908563,
+    7.96116808,
+    7.57204861,
+    7.10734052,
+    6.57265713,
+    5.97361172,
+    5.31581763,
+    4.60488814,
+    3.84643656,
+    3.04607621,
+    2.20942040,
+    1.34208241,
+    0.44967558,
+    -0.46218681,
+    -1.38789144,
+    -2.32182500,
+    -3.25837419,
+    -4.19192570,
+    -5.11686623,
+    -6.02758247,
+    -6.91846110,
+    -7.78388883,
+    -8.61825235,
+    -9.41593835,
+    -10.17133352,
+    -10.87882456,
+    -11.53279815,
+    -12.12764100,
+    -12.65773980,
+    -13.11748123,
+    -13.50125200,
+    -13.80343879,
+    -14.01842830,
+    -14.14060723,
+    -14.16436225,
+    -14.08408008,
+    -13.89414739,
+    -13.58895089,
+    -13.16287727,
+    -12.61031321,
+    -11.92564542,
+    -11.10326059,
+    -10.13754541,
+    -9.02288657,
+    -7.75367076,
+    -6.32428468,
+    -4.72911503,
+    -2.96254849,
+    -1.01897176,
+    1.10722847,
+    3.42166550,
+    5.92995265,
+    8.63770321,
+    11.55053050,
+    14.66926935,
+    6.86179709,
+    -5.47290466,
+    -13.83246355,
+    -18.66023243,
+    -20.39956416,
+    -19.49381157,
+    -16.38632753,
+    -11.52046487,
+    -5.33957647,
+    1.71298484,
+    9.19386620,
+    16.65971477,
+    23.66717768,
+    29.77290209,
+    34.53353516,
+    37.50572402,
+    38.25154792,
+    36.50596565,
+    32.20857414,
+    25.31081084,
+    15.77278173,
+    3.77074445,
+    -10.29313973,
+    -26.00608936,
+    -42.95532304,
+    -60.72805933,
+    -78.91151682,
+    -97.09291408,
+    -114.85946968,
+    -131.79840221,
+    -147.49693024,
+    -161.54227235,
+    -173.52164712,
+    -183.02227312,
+    -189.63136892,
+    -192.93615311,
+    -192.52384426,
+    -187.98166096,
+    -178.89682177,
+    -164.85654527,
+    -145.44805004,
+    -120.25855466,
+    -88.87527770,
+    -50.88543775,
+    -5.87625337,
+    46.56007116,
+    104.43504592,
+    159.52668786,
+    202.61238918,
+    224.46954207,
+    215.87553872,
+    167.60777130,
+    70.44363202,
+    5.46110638,
+    141.75857149,
+    230.42498382,
+    276.55540391,
+    287.68451731,
+    271.34700958,
+    235.07756626,
+    186.41087289,
+    132.88161504,
+    82.02447824,
+    41.37414805,
+    18.46531002,
+    16.85424129,
+    19.09321438,
+    21.24241296,
+    23.30206825,
+    25.27241149,
+    27.15367391,
+    28.94608674,
+    30.64988121,
+    32.26528857,
+    33.79254002,
+    35.23186682,
+    36.58350019,
+    37.84767137,
+    39.02461158,
+    40.11455206,
+    41.11772404,
+    42.03435875,
+    42.86468742,
+    43.60894129,
+    44.26735159,
+    44.84014956,
+    45.32756641,
+    45.72983339,
+    46.04718172,
+    46.27984264,
+    46.42804739,
+    46.49202718,
+    46.47201326,
+    46.36823686,
+    46.18092921,
+    45.91032154,
+    45.55664508,
+    45.12013106,
+    44.60101073,
+    43.99951530,
+    43.31587601,
+    42.55032410,
+    41.70309079,
+    40.77461777,
+    39.76848476,
+    38.69068156,
+    37.54725968,
+    36.34427059,
+    35.08776577,
+    33.78379673,
+    32.43841493,
+    31.05767187,
+    29.64761904,
+    28.21430791,
+    26.76378998,
+    25.30211674,
+    23.83533966,
+    22.36951024,
+    20.91067996,
+    19.46490031,
+    18.03822277,
+    16.63669883,
+    15.26637998,
+    13.93331770,
+    12.64356348,
+    11.40316880,
+    10.21818516,
+    9.09466403,
+    8.03865691,
+    7.05621528,
+    6.15339062,
+    5.33623443,
+    4.61079818,
+    3.98313337,
+    3.45929148,
+    3.04532400,
+    2.74728241,
+    2.57121821,
+    2.52318286,
+    2.60922788,
+    2.83540473,
+    3.20776490,
+    3.73235989,
+    4.41524117,
+    5.26246024,
+    6.28006857,
+    7.47411766,
+    8.85065900,
 )
 
 DATA_SAMPLE_NORMALISED: tuple = (
@@ -1549,15 +1549,19 @@ def test_interpolate(self) -> None:
             self._non_uniform_sd.shape.end,
             1,
         )
-        sd = reshape_sd(self._non_uniform_sd, shape, "Interpolate")
+        sd = reshape_sd(
+            self._non_uniform_sd,
+            shape,
+            "Interpolate",
+        )
         np.testing.assert_allclose(
             sd.values,
             DATA_SAMPLE_INTERPOLATED_NON_UNIFORM,
             atol=TOLERANCE_ABSOLUTE_TESTS,
         )
         assert sd.shape == SpectralShape(
-            np.ceil(self._non_uniform_sd.shape.start),
-            np.floor(self._non_uniform_sd.shape.end),
+            self._non_uniform_sd.shape.start,
+            self._non_uniform_sd.shape.end,
             1,
         )
 
@@ -1833,8 +1837,8 @@ def test_interpolate(self) -> None:
                 atol=TOLERANCE_ABSOLUTE_TESTS,
             )
         assert msds.shape == SpectralShape(
-            np.ceil(self._non_uniform_sample_msds.shape.start),
-            np.floor(self._non_uniform_sample_msds.shape.end),
+            self._non_uniform_sample_msds.shape.start,
+            self._non_uniform_sample_msds.shape.end,
             1,
         )